Chapter 3. Working with Files and Directories - Permissions, Commands, File Name Expansion, and Wild Cards

CONTENTS

Chapter 3. Working with Files and Directories - Permissions, Commands, File Name Expansion, and Wild Cards

•  Introduction
•  Permissions
•  Absolute and Relative Path Names
•  File Name Expansion and Wild Cards
•  pwd and cd
•  chmod
•  cp
•  mv
•  mkdir
•  rm
•  rmdir
•  Using Commands
•  Manual Pages for Some Commands Used in Chapter 3

Introduction

A variety of topics related to UNIX file system structure, navigation, and daily use are covered in this chapter, including:

• Permissions

• Absolute and relative path names

• File name expansion and wild cards

• Several commands including: pwd, cd, chmod, cp, mv, mkdir, rm, rmdir

• Examples of using many commands

Permissions

The best place to begin discussing permissions is by issuing the ls command, which lists the contents of directories. Permissions are the means by which files and directories are made secure on your UNIX system. Because UNIX is multi-user, potentially thousands of users could be accessing the files on a system. Permissions controls who has access to what files.

Here is an example ls -l command and output:

$ ls -l sort  -rwxr-x--x   1 marty     users     120 Jul 26 10:20 sort 

Issuing this command has produced a lot of information relating to a file called sort. Let's begin to understand what this listing has produced by analyzing the first set of characters (-rwxr-x--x). This set of characters is made up of four distinct fields, as shown in Figure 3-1.

Figure 3-1. Permissions for File sort

The first character in this group is related to the file type. I covered some file types earlier, but the ls -l command does not analyze files to the same level of detail. Among the types of files ls -l will list are shown in Figure 3-2:

Figure 3-2. File Types of the ls Command

Keep in mind the file types can vary slightly from one UNIX variant to another. The file types listed in Figure 3-2 are common to most UNIX variants. For every file on the system, UNIX supports three classes of access:

• User access (u). Access granted to the owner of the file.

• Group access (g). Access granted to members of the same group as the owner of the file.

• Other access (o). Access granted to everyone else.

These access rights are defined by the position of read (r), write (w), and execute (x) when the long listing command is issued. For the long listing (ls -l) issued earlier, you see the permissions in Table 3-1.

Table 3-1. Long Listing Permissions for the File sort

Access	User Access	Group Access	Other
Read	r	r	-
Write	w		-
Execute	x	x	x

Permissions are not granted where a "-" (hyphen) appears. In addition, there are other permissions such as s, S, t, and T, which I don't cover at this time.

You can see that access rights are arranged in groups of three: three groups of permissions with three access levels each. The owner, in this case marty, has read, write, and execute permissions on the file. Anyone in the group users is permitted read and execute access to the file. other is permitted only execute access of the file.

The definitions of read, write, and execute differ somewhat for files and directories. Here is what you can do if you have read, write, and execute permissions for files:

read You have permission to read the file.

write You have permission to change and to write to the file.

execute You can run, or execute, the program.

Here is what you can do if you have read, write, and execute permissions for directories:

read You can list the contents of the directory.

write You can create files in the directory, delete files in the directory, and create subdirectories in the directory.

execute You can change to this directory using the cd command, which we'll cover shortly.

We will cover permissions again when the chmod command is described.

Absolute and Relative Path Names

We have already covered two topics that can serve as the basis for a discussion of absolute and relative path names: some important directories on the system and user login. If you take a look at the user denise and the way some of her files can be organized, we can get to the bottom of relative and absolute path names quickly.

The UNIX file system covered in Chapter 2 showed a hierarchy. In this hierarchy, there was the root (/) directory at the top, and files and directories were below root. The two means by which you can traverse this hierarchy to get to a "lower" point are with absolute path names and relative path names. Let's take a closer look at the files and directories that denise may have in her user area.

First of all, we'll assume that denise has many files. This activity is one of the things users do - create files. In addition, your system administrator has provided several default files for purposes such as defining your user environment after login (we'll get into this in a lot more detail in upcoming chapters). denise probably has many files under her user area, and subdirectories as well. Her user area may look something like that shown in Figure 3-3:

Figure 3-3. Home Directory for denise

Most users will have their home directory under /home (and who said UNIX doesn't make any sense?). If you want to get to a subdirectory of denise using an absolute path name, you traverse the hierarchy using the complete path. To get to the directory.netscape-cache under denise, you could view the absolute path as shown in Figure 3-4:

Figure 3-4. Absolute Path

You are progressing from root (/), to home, todenise, and finally to the directory.netscape-cache. The change directory (cd) command which you issue looks like the following:

$ cd /home/denise/.netscape-cache 

This is an absolute path because it starts at root and progresses through the hierarchy. No matter what directory you are currently working in, even if it is.netscape-cache, you could use the absolute path name. In many cases, however, you may not need to issue an absolute path name. You may be so close to the file or directory you wish to access that the absolute path would be a waste of time for you. If, for instance, you are already in /home/denise, then you could change to.netscape-cache using a relative path name easily:

$ cd .netscape-cache 

The relative path name is shorter because you don't begin with a slash (/) that brings you back up to the top of the hierarchy to work your way down. Instead, you are starting at some point in the file system hierarchy, such as /home/denise, and entering a path relative to that directory, such as.netscape-cache.

File Name Expansion and Wild Cards

Before we cover additional file system related commands, it is worth taking a look at file name expansion. An overview of file name expansion is useful to ensure that you're comfortable with this topic before we cover additional commands.

Table 3-2 lists some common file name expansion and pattern matching.

Table 3-2. File Name Expansion and Pattern Matching

Character(s)	Example	Description
*	1) ls *.c	Match zero or more characters
?	2) ls conf.?	Match any single character
[list]	3) ls conf.[co]	Match any character in list
[lower-upper]	4) ls libdd.9873[5-6].sl	Match any character in range
str{str1,str2,str3,...}	5) ls ux*.{700,300}	Expand str with contents of {}
~	6) ls -a ~	Home directory
~username	7) ls -a ~gene	Home directory of username

The following descriptions of the examples shown in Table 3-2 are more detailed:

1. To list all files in a directory that end in ".c", you could do the following:

   $  ls *.c            conf. SAM.c  conf.c 

   

2. To find all the files in a directory named "conf" with an extension of one character, you could do the following:

   $  ls conf.?            conf.c  conf.o  conf.1 

3. To list all the files in a directory named "conf" with only the extension "c" or "o," you could do the following:

   $  ls conf.{co}            conf.c  conf.o 

4. To list files with similar names but a field that covers a range, you could do the following:

   $  ls libdd9873[5-6].sl            libdd98735.sl  libdd98736.sl 

5. To list files that start with "ux" and have the extension "300" or "700," you could do the following:

   $  ls ux*.{700,300}            uxbootlf.700  uxinstfs.300 

6. To list the files in your home directory, you could use ~ (tilde:

   $  ls -a ~            .       .cshrc.org   .login       .shrc.org            ..      .exrc        .login.org   .cshrc                    .history     .profile 

7. To list the files in the home directory of a user, you could do the following:

   $  ls -a ~gene           .          .history    splinedat   under.des           ..         .login      trail.txt   xtra.part           .chsrc     .login.org   ESP-File           .cshrc.org .profile    Mail           .exrc      .shrc.org   opt 

pwd and cd

When we covered absolute and relative path names, we used the cd command to change directory. You can be at any point in the file system hierarchy and use cd to change to the desired directory, provided that you have the necessary permissions to change to that directory.

We can change directory using an absolute path name as shown in the following example:

$ cd /home/denise/.netscape-cache 

Regardless of your current location in the file system hierarchy, this changes you to the directory /home/denise/.netscape-cache. If, however, your current location in the file system hierarchy is /home/ denise, then you could use a relative path name to change to.netscape-cache, as shown in the following example:

$ cd .netscape-cache 

In order to change directory to a place in the file system relative to your current location, you need a way to determine your current location. The pwd command, for present working directory, can do this for you. Going back to the previous example in which we changed directories using the relative path, we could have first issued the pwd command to see that our location was /home/denise, as shown in the following example

$ pwd  /home/denise  $ cd .netscape-cache  $ pwd  $ /home/denise/.netscape-cache  $ 

pwd takes some of the mystery out of determining your current directory.

Let's now take a look at moving up a level in the directory tree using two dots:

$ pwd  /home/denise/.netscape-cache  $ cd ..  $ pwd  /home/denise  $ 

The two-dot notation moves you to the parent directory of your current directory.

To return to your home directory, you could issue the cd command with no arguments as shown in the following example:

$ pwd  /tmp  $ cd  $ pwd  /home/denise  $ 

This shows that no matter what your current location in the file system hierarchy, you can always get back quickly to your home directory. I don't get into shell parameters for some time, but there is a shell parameter which defines your home location, as shown in the following example:

$ pwd  /tmp  $ cd $HOME  $ pwd  /home/denise  $ 

Using the pwd and cd commands, you can always obtain your current directory and change to any directory.

cd - Change to a new current directory.

 

Arguments
	none	Change to home directory. This is defined by the HOME environment variable.
	..	The two dot notation moves you to the parent directory of your current directory.
	path	You can specify either an absolute or relative path to change to.
pwd Present Working Directory, so you know your current location.

Examples

$ pwd  /home/denise/.netscape-cache  $ cd .. 

$ pwd  /home/denise  $ 

chmod

The chmod command is used to change the permissions on a file. Let's start our discussion of chmod with the listing of the file sort shown earlier:

$ ls -l sort  -rwxr-x--x   1 marty    users    120 Jul 26 10:20 sort 

Figure 3-5 shows a breakdown of the permissions on sort.

Figure 3-5. Permissions of File sort

You have very little control over the type of file defined. You do, however, have a great deal of control over the permissions of this file if it belongs to you. The chmod command is used to change the permissions on a file or directory. If you are the owner of the file, you can have a field day changing the permissions on the file.

There are two means by which you can change the permissions: symbolic or numeric. I focus first on the numeric mode, because the numbers involved are easy to manage and I sometimes find that new UNIX users get hung up on the meaning of some of the symbols. I'll then cover the symbols and include the symbol meanings in the chmod summary. I decided to use the symbols in the summary because the numeric mode, which I much prefer, is becoming obsolete. In some UNIX variants, the chmod manual page is strewn with references to "obsolescent form" whenever the numeric mode is covered.

First of all, what do I mean by numbers? Looking at the numbers for sort, we see permissions of 751: 7 for owner (hundreds position), 5 forgroup (tens position), and 1 for other (ones position). Figure 3-6 helps with the meanings of the positions:

Figure 3-6. Numerical Permissions Summary

Selecting the desired permissions for owner, group, andother, you use the chmod command to assign those permissions to a file or directory. Some of these permission possibilities are infrequently used, such as execute only, because you usually need to have read access to a file in order to execute it; however, I included all possibilities in Figure 3-6 for completeness. In addition to the permission mode bits shown in Figure 3-6, some miscellaneous mode bits also exist that you don't need to be concerned with at this time.

If you decide that you would like to add write permission of the file sort for group and remove all permissions for other, you would simply execute the chmod command with the appropriate numeric value. The following set of commands first lists the existing permissions for sort, then it changes the permissions on sort, and finally it lists the new permissions on sort:

$ ls -l sort  -rwxr-x--x   1 marty     users      120 Jul 26 10:20 sort  $ chmod 770 sort  $ ls -l sort  -rwxrwx---   1 marty     users      120 Jul 26 10:20 sort 

The same set of commands to change the permissions using the symbolic mode would be:

$ ls -l sort  -rwxr-x--x   1 marty     users      120 Jul 26 10:20 sort  $ chmod g+w,o-x sort  $ ls -l sort  -rwxrwx---   1 marty     users      120 Jul 26 10:20 sort 

In symbolic mode, you issue the chmod command and specify who will be affected by the change [user (u), group (g), other (o), or all (a)], the operation you wish to perform [add (+), delete (-), or replace (=)] on permissions, and the permission you wish to specify [read (r), write (w), or execute (x)]. In the previous example using symbolic mode, write (w) permission is being added (+) for group (g), and execute (x) permission is being removed (-) for other (o).

The following is a summary of some of the more commonly used symbols of chmod:

chmod - Change permissions of specified files using the following symbolic mode list.

 

Symbol of who is affected:
	u	User is affected.
	g	Group is affected.
	o	Other is affected.
	a	All users are affected.
Operation to perform:
	+	Add permission.
	-	Remove permission.
	=	Replace permission.
Permission specified:
	r	Read permission.
	w	Write permission.
	x	Execute permission.
	u	Copy user permissions.
	g	Copy group permissions.
	o	Copy other permissions.

cp

The cp command is used to copy a file from one location to another location. You do not alter the original file when you perform a copy. Provided that you have access to the destination directory to which you wish to copy a file, you can place as many copies of a file in that destination as you wish.

The following bullet list describes some of the types of copies you can perform with cp. Because there are many file types in UNIX (as covered in Chapter 2) and you have many ways to specify path names for the source and destination files being copied, this list might help you understand the many ways cp can be used:

• Copy a source file to a new file name.

• Copy several source files to a different directory.

• Copy several source files to the same directory.

• Copy an entire directory to a different directory.

• Copy several directories to different directories.

The following is an example of copying a file to a new file name within the same directory:

$ cp krsort krsort.sav 

What if the file krsort.sav already exists? The answer is that it is replaced by the new krsort.sav being copied. To prevent such mishaps (officially called an overwrite) from occurring, you use the -i option to cp. -i asks you whether you wish to overwrite the file before the copy takes place. If your response is affirmative, then the old file is overwritten with the new file.

The following example first shows a listing of the contents of a directory. Using cp with the -i option, we copy the file krsort.c to krsortorig.c, a file that already exists. By responding n when asked whether we want to overwrite krsortorig.c, the file is not overwritten and no copy takes place:

$ ls -l  total 168  -rwxr-xr-x   1 denise  users     34592 Oct 31 11:27 krsort  -rwxr-xr-x   1 denise  users      3234 Oct 31 11:27 krsort.c  -rwxr-xr-x   1 denise  users    32756 Oct 31 11:27 krsort.dos  -rw-r--r--   1 denise  users      9922 Oct 31 11:27 krsort.q  -rwxr-xr-x  1 denise  users    3085 Oct 31 11:27 krsortorig.c  $ cp -i krsort.c krsortorig.c  overwrite krsortorig.c? (y/n) n  $ 

cp - Copy files and directories.

 

Options
	-i	Interactive copy whereby you are prompted to confirm that you wish to overwrite an existing file.
	-f	Force existing files to be overwritten by files being copied if a conflict in file names occurs.
	-p	Preserve permissions when copying.
	-r	Copy recursively.
	-R	Copy recursively, except when permissions are different.

mv

The mv command is used to move a file or directory from one location to another location. You can also move multiple files.

The following example shows a listing of a directory, the move of file krsort.c to krsort.test.c within this directory, and a listing of the directory showing that the file has been moved:

$ ls -l  total 168  -rwxr-xr-x   1 denise   users   34592 Oct 31 15:17 krsort  -rwxr-xr-x   1 denise   users    3234 Oct 31 15:17 krsort.c  -rwxr-xr-x   1 denise   users    2756 Oct 31 15:17 krsort.dos  -rw-r--r--   1 denise   users    9922 Oct 31 15:17 krsort.q  -rwxr-xr-x   1 denise   users    3085 Oct 31 15:17 krsortorig.c  $ mv krsort.c krsort.test.c  $ ls -l  total 168  -rwxr-xr-x   1 denise  users  34592 Oct 31 15:17 krsort  -rwxr-xr-x   1 denise  users  32756 Oct 31 15:17 krsort.dos  -rw-r--r--   1 denise  users   9922 Oct 31 15:17 krsort.q  -rwxr-xr-x   1 denise  users   3234 Oct 31 15:17 krsort.test.c  -rwxr-xr-x   1 denise  users   3085 Oct 31 15:17 krsortorig.c  $ 

What if the destination file already exists? You guessed it, UNIX is more than happy to write over the destination file. Using the -i option, mv asks you to confirm overwriting a file before it does so. The following example shows an attempt to move krsort.test.c to krsortorig.c. The user is alerted to the fact that krsortorig.c already exists and chooses not to let the move take place:

$ ls -l  total 168  -rwxr-xr-x  1 denise  users    34592 Oct 31 15:17 krsort  -rwxr-xr-x  1 denise  users    32756 Oct 31 15:17 krsort.dos  -rw-r--r--  1 denise  users     9922 Oct 31 15:17 krsort.q  -rwxr-xr-x  1 denise  users     3234 Oct 31 15:17 krsort.test.c  -rwxr-xr-x  1 denise  users     3085 Oct 31 15:17 krsortorig.c  $ mv -i krsort.test.c krsortorig.c  remove krsortorig.c? (y/n) n  $ ls -l  total 168  -rwxr-xr-x  1 denise  users    34592 Oct 31 15:17 krsort  -rwxr-xr-x  1 denise  users    32756 Oct 31 15:17 krsort.dos  -rw-r--r--  1 denise  users     9922 Oct 31 15:17 krsort.q  -rwxr-xr-x  1 denise  users     3234 Oct 31 15:17 krsort.test.c  -rwxr-xr-x  1 denise  users     3085 Oct 31 15:17 krsortorig.c  $ 

Because the response was not in the affirmative, the move does not take place, and the original krsortorig.c remains intact.

mv - Move files and directories.

 

Options
	-i	Interactive move whereby you are prompted to confirm that you wish to overwrite an existing file.
	-f	Force existing files to be overwritten by files being moved if a conflict in file names occurs.
	-p	Preserve permissions when moving.

mkdir

How nice it would be to have a commandtomake a directoryany time you wish. You could then use this command to create directories and thereby organize your files in multiple directories in a way similar to organizing files in a filing cabinet. The mkdir command allows you to do just that - make a directory.

This is an incredibly simple command. You specify the name of the directory to create. In the following example, we'll look at the contents of a directory with the ls command, use mkdir to make the directory named default.permissions, and then perform another ls to see the new directory:

$ ls -l  total 2  drwxr-xr-x   2 denise   users       1024 Oct 31 11:27 krsort.dir.old  $ mkdir default.permissions  $ ls -l  total 4  drwxr-xr-x   2 denise   users       1024 Oct 31 11:27 krsort.dir.old  drwxr-xr-x   2 denise   users         24 Oct 31 11:32 default.permissions  $ 

The new directory has been produced with default permissions for the user denise. group and other have both read and execute permissions for this directory.

What if you wanted to create a directory with specific permissions on it instead of default permissions? You could use the -m option to mkdir and specify the mode or permissions you wanted. To give all users read permission on the krsort.dir.new directory, you issue the following:

$ mkdir -m "a=r" read.permissions  $ ls -l  total 6  drwxr-xr-x   2 denise   users       1024 Oct 31 11:27 krsort.dir.old  drwxr-xr-x   2 denise   users         24 Oct 31 11:32 default.permissions  dr--r--r--   2 denise   users         24 Oct 31 11:33 read.permissions  $ 

Remember the symbolic versus numeric mode of permissions? This mkdir command shows the symbolic mode, which, although I do not like it as much as the numeric mode, should be used because the numeric mode is becoming obsolete.

You don't have to stop at creating a directory with only one level of depth. With the -p option, you can create a new directory with any number of subdirectories in it. Intermediate directories are created with the -p option. Let's now create a directory named level1, with the directory level2 beneath it, and the directory level3 below level2 in the following example. The ls command with the -R option recursively lists the directories below level1:

$ mkdir -p level1/level2/level3  $ ls -R level1  level2  level1/level2:  level3  level1/level2/level3:  $ 

After creating the directory level1 and issuing thels command, we can see that level2 is indeed beneath level1, andlevel3 is beneath level2.

mkdir - Create specified directories.

 

Options
	-m	Specify the mode (permissions) of the directory.
	-p	Create intermediate directories to achieve the full path. If you want to create several layers of directories down, you use -p.

rm

The rm command removes one or more files from a directory and can also be used to remove the directory itself. Going back to our earlier discussion on permissions, you must have both write and execute permissions on a directory in order to remove a file from it. If you own the directory from which you are going to remove files, then you can probably remove files from it. If, however, you don't have the appropriate permissions on a directory, then the rm fails.

As with some of the other commands we have covered, you can use the -i option, which asks you to confirm each file as it is removed. This means that if you are asked whether you really wish to remove a file and you respond n, then the file is not removed. If you respond y, the file is removed.

You can also use the -r (or -R) option to recursively delete the contents of directories and then delete the directories. This means you can recursively delete the files and directories specified. If there is any question in your mind about whether or not you wish to recursively delete files and directories, then use the -i option along with -r.

You can use the -f option to remove files and directories, which performs removes without asking you to confirm them.

The following example performs a long listing of the directory krsort.dir.new, interactively prompts the user to see whether he or she wants to delete the files in this directory, and then lists the contents of this directory again, showing that all files have not been deleted because the user responded n:

$ ls -l krsort.dir.new  total 168  -rwxr-xr-x  1 denise  users   34592 Oct 27 18:44 krsort  -rwxr-xr-x  1 denise  users   3234 Oct 27 18:46 krsort.c  -rwxr-xr-x  1 denise  users  32756 Oct 27 18:46 krsort.dos  -rw-r--r--  1 denise  users   9922 Oct 27 18:46 krsort.q  -rwxr-xr-x  1 denise  users   3085 Oct 27 18:46 krsortorig.c  $ rm -i krsort.dir.new/*  ../krsort.dir.new/krsort: ? (y/n) n  ../krsort.dir.new/krsort.c: ? (y/n) n  ../krsort.dir.new/krsort.dos: ? (y/n) n  ../krsort.dir.new/krsort.q: ? (y/n) n  ../krsort.dir.new/krsortorig.c: ? (y/n) n  $ ls -l krsort.dir.new  total 168  -rwxr-xr-x  1 denise  users   34592 Oct 27 18:44 krsort  -rwxr-xr-x  1 denise  users    3234 Oct 27 18:46 krsort.c  -rwxr-xr-x  1 denise  users   32756 Oct 27 18:46 krsort.dos  -rw-r--r--  1 denise  users    9922 Oct 27 18:46 krsort.q  -rwxr-xr-x  1 denise  users    3085 Oct 27 18:46 krsortorig.c  $ 

Note that the response to being asked whether the file should be deleted was n in all cases. This means that none of the files have been removed. A y response to any question results in that file being removed from the directory. To interactively delete a directory, you combine the options -i and -r of the rm command. If, however, you do not delete every file in a directory, then the directory is not removed if the -i option is used. The first part of the following example shows all but the file krsort being removed from the directory krsort.dir.new. The directory is not deleted because this file still exists. When the file is removed in the second part of this example, the directory itself is then deleted:

$ rm -ir krsort.dir.new  directory krsort.dir.new: ? (y/n) y  krsort.dir.new/krsort: ? (y/n) n  krsort.dir.new/krsort.c: ? (y/n) y  krsort.dir.new/krsort.dos: ? (y/n) y  krsort.dir.new/krsort.q: ? (y/n) y  krsort.dir.new/krsortorig.c: ? (y/n) y  krsort.dir.new: ? (y/n) y  rm: directory krsort.dir.new not removed. Directory not  empty  $ rm -ir krsort.dir.new  directory krsort.dir.new: ? (y/n) y  krsort.dir.new/krsort: ? (y/n) y  krsort.dir.new: ? (y/n) y  $ 

rm - Remove files and directories.

 

Options
	-i	Interactive remove whereby you are prompted to confirm that you wish to remove an existing file.
	-f	Force files to be removed.
	-r	(-R) Recursively remove the contents of the directory and then the directory itself.

rmdir

The rmdir command removes one or more directories. The directory must be empty in order to be removed or you must use the -f option. You can also specify more than one directory to be removed. Going back to our earlier discussion on permissions, you must have both write and execute permissions on the parent of a directory to be removed in order to remove it.

As with some of the other commands we have covered, you can use the -i option, which asks you to confirm each directory as it is removed. This means that if you are asked whether you really wish to remove a directory and you respond n, then it is not removed. If you respond y, it is removed.

The order in which you specify directories are to be removed is significant. If you want to remove both a directory and its subdirectory, you must specify the subdirectory to be removed first. If you specify the parent directory rather than its subdirectory to be removed first, the removal of the parent directory fails because it is not empty.

You can use the -f option to force the removal of directories, an action that performs removal without asking you to confirm them.

The following example performs a long listing of the directory krsort.dir.new, showing that this directory has in it a file called.dotfile. When we attempt to remove this directory with rmdir, a message is displayed informing us that this directory is not empty. The file .dotfile in this directory prevents the rmdir command from removing krsort.dir.new. After removing.dotfile, we are able to remove the directory with rmdir:

$ ls -al ../krsort.dir.new  total 4  drwxr-xr-x   2 denise   users      1024 Oct 27 18:57 .  drwxrwxr-x   4 denise   users      1024 Oct 27 18:40 ..  -rw-r--r--   1 denise   users         0 Oct 27 18:56 .dotfile  $ rmdir -i ../krsort.dir.new  ../krsort.dir.new: ? (y/n) y  rmdir: ../krsort.dir.new: Directory not empty  $ rm ../krsort.dir.new/.dotfile  $ rmdir -i ../krsort.dir.new  ../krsort.dir.new: ? (y/n) y  $ 

rmdir has now successfully removed krsort.dir.new because.dotfile is gone:

rmdir - Remove directories.

 

Options
	-i	Interactive remove whereby you are prompted to confirm that you wish to remove a directory
	-f	Force directories to be removed.
	-p	If, after removing a directory, the parent directory is empty, then remove it also. This goes on until a parent directory is encountered that is not empty.

Using Commands

Using the cd, pwd, ls, mkdir, and cp Commands

Now that we have covered some of these commands in an "isolated" fashion, let's put some of the commands together.

Let's start by viewing the hierarchy of a directory under denise's home directory, called krsort.dir.old, as shown in Figure 3-7:

Figure 3-7. /home/denise/krsort.dir.old

$ cd /home/denise/krsort.dir.old  $ pwd  /home/denise/krsort.dir.old  $ ls -l  total 168  -rwxr-xr-x   1 denise  users   34592 Oct 27 18:20 krsort  -rwxr-xr-x   1 denise  users    3234 Oct 27 17:30 krsort.c  -rwxr-xr-x   1 denise  users   32756 Oct 27 17:30 krsort.dos  -rw-r--r--   1 denise  users    9922 Oct 27 17:30 krsort.q  -rwxr-xr-x   1 denise  users   3085 Oct 27 17:30 krsortorig.c  $ 

We can then make a new directory called krsort.dir.new and copy a file to it, as shown in Figure 3-8:

Figure 3-8. /home/denise/krsort.dir.new

$ mkdir ../krsort.dir.new  $ cp krsort ../krsort.dir.new  $ ls -l ../krsort.dir.new  total 68  -rwxr-xr-x   1 denise   users     34592 Oct 27 18:27 krsort  $ 

Now let's try the -i option to cp. If we attempt to copy a file to an existing file name, we'll be asked if we wish to overwrite the destination file. We are alerted to the fact that the destination file already exists and we can then select a new name for the file we wish to copy, as shown in Figure 3-9:

Figure 3-9. /home/denise/krsort.dir.new/krsort.new.name Added

$ pwd  /users/denise/krsort.dir.old  $ cp -i krsort ../krsort.dir.new  overwrite ../krsort.dir.new/krsort? (y/n) n  $ cp krsort ../krsort.dir.new/krsort.new.name  $ ls -l ../krsort.dir.new  total 136  -rwxr-xr-x   1 denise   users    34592 Oct 27 18:27 krsort  -rwxr-xr-x     1  denise      users       34592 Oct 27 18:29  krsort.new.name  $ 

We can also use a wild card with cp to copy all files in krsort.dir.old to krsort.dir.new, as shown in Figure 3-10:

Figure 3-10. All Files Copied to /home/denise/krsort.dir.new

$ cp * ../krsort.dir.new  $ ls -l ../krsort.dir.new  total 236  -rwxr-xr-x   1 denise   users    34592 Oct 27 18:30 krsort  -rwxr-xr-x   1 denise   users     3234 Oct 27 18:30 krsort.c  -rwxr-xr-x   1 denise   users    32756 Oct 27 18:30 krsort.dos  -rwxr-xr-x   1 denise   users    34592 Oct 27 18:29  krsort.new.name  -rw-r--r--   1 denise   users     9922 Oct 27 18:30 krsort.q  -rwxr-xr-x   1 denise   users    3085 Oct 27 18:30 krsortorig.c  $ 

Using the mv Command

Let's start over at the point where the krsort.dir.new directory is empty, as shown in Figure 3-11:

Figure 3-11. Empty /home/denise/krsort.dir.new Directory

We can now move the file krsort to the krsort.dir.new directory, as shown in Figure 3-12:

Figure 3-12. krsort Moved to /krsort.dir.new

$ mv krsort ../krsort.dir.new  $ ls -l ../krsort.dir.new  total 68  -rwxr-xr-x   1 denise   users     34592 Oct 27 18:20 krsort  $ 

If we now attempt to move krsort to the krsort.dir.new directory with the -i option and write over the file krsort, we getthe following:

$ mv -i krsort ../krsort.dir.new/krsort  remove ../krsort.dir.new/krsort? (y/n) n  $ 

Because we used the -i option to mv, we areasked whetherwe wish to allow a file to be overwritten with the move. Because we responded n to the question, the file is not overwritten.

We can also use a wild card with the mv command to copy all files from the krsort.dir.old directory to the krsort.dir.new directory. Without the -i option, any files in the krsort.dir.new directory are overwritten by files that have the same name, as shown in Figure 3-13:

Figure 3-13. All Files Moved to /home/denise/krsort.dir.new

$ mv * ../krsort.dir.new  $ ls -l ../krsort.dir.new  total 168  -rwxr-xr-x   1 denise   users   34592 Oct 27 18:44 krsort  -rwxr-xr-x   1 denise   users    3234 Oct 27 18:46 krsort.c  -rwxr-xr-x   1 denise   users   32756 Oct 27 18:46 krsort.dos  -rw-r--r--   1 denise   users    9922 Oct 27 18:46 krsort.q  -rwxr-xr-x   1 denise   users    3085 Oct 27 18:46 krsortorig.c  $ 

Down and Dirty with the rm and rmdir Commands

The most feared command in the UNIX world, with good reason I might add, is the rm command. rm removes whatever you want whenever you want, with no questions asked unless you use the -i option.

Want to blow away your system instantly? rm would be more than happy to help you. As an average user, and not the system administrator, you probably do not have the permissions to do so. It is, however, unnerving to know that this is a possibility. In addition, it is likely that you have permissions remove all of your own files and directories. All of this can be easily avoided by simply using the -i option to rm.

Let's assume that krsort.dir.new and krsort.dir.old are identical directories, as shown in Figure 3-14:

Figure 3-14. /home/denise/krsort.dir.old and /home/denise/krsort.dir.new Identical

To interactively remove files from krsort.dir.new, you do the following:

$ rm -i ../krsort.dir.new/*  ../krsort.dir.new/krsort: ? (y/n) n  ../krsort.dir.new/krsort.c: ? (y/n) n  ../krsort.dir.new/krsort.dos: ? (y/n) n  ../krsort.dir.new/krsort.q: ? (y/n) n  ../krsort.dir.new/krsortorig.c: ? (y/n) n  $ ls -l ../krsort.dir.new  total 168  -rwxr-xr-x   1 denise   users    34592 Oct 27 18:44 krsort  -rwxr-xr-x   1 denise   users     3234 Oct 27 18:46 krsort.c  -rwxr-xr-x   1 denise   users    32756 Oct 27 18:46 krsort.dos  -rw-r--r--   1 denise   users     9922 Oct 27 18:46 krsort.q  -rwxr-xr-x   1 denise   users    3085 Oct 27 18:46 krsortorig.c  $ 

This obviously resulted in nothing being removed from krsort.dir.new because we responded n when asked whether we wanted to delete files.

Let's now go ahead and add a file beginning with a "." (period) to krsort.dir.new. The touch command does just that, it touches a file to create it with no contents, as shown in Figure 3-15 (touch can also be used to update the time stamp of an existing file):

Figure 3-15. /home/denise/krsort.dir.new with.dotfile

$ touch ../krsort.dir.new/.dotfile  $ ls -al ../krsort.dir.new  total 172  drwxr-xr-x   2 denise   users    1024 Oct 27 18:54 .  drwxrwxr-x   4 denise   users    1024 Oct 27 18:40 ..  -rw-r--r--   1 denise   users       0 Oct 27 18:56 .dotfile  -rwxr-xr-x   1 denise   users   34592 Oct 27 18:44 krsort  -rwxr-xr-x   1 denise   users    3234 Oct 27 18:46 krsort.c  -rwxr-xr-x   1 denise   users   32756 Oct 27 18:46 krsort.dos  -rw-r--r--   1 denise   users    9922 Oct 27 18:46 krsort.q  -rwxr-xr-x   1 denise   users    3085 Oct 27 18:46 krsortorig.c  $ 

If we now attempt to remove files using the same rm command earlier issued, we'll see the following, as shown in Figure 3-16:

Figure 3-16. Only.dotfile Left in /home/denise/krsort.dir.new

$ rm -i ../krsort.dir.new/*  ../krsort.dir.new/krsort: ? (y/n) y  ../krsort.dir.new/krsort.c: ? (y/n) y  ../krsort.dir.new/krsort.dos: ? (y/n) y  ../krsort.dir.new/krsort.q: ? (y/n) y  ../krsort.dir.new/krsortorig.c: ? (y/n) y  $ ls -al ../krsort.dir.new  total 4  drwxr-xr-x   2 denise   users       1024 Oct 27 18:57 .  drwxrwxr-x   4 denise   users       1024 Oct 27 18:40 ..  -rw-r--r--   1 denise   users          0 Oct 27 18:56 .dotfile 

The "*" used as a wild card with the rm command does not remove the file.dotfile. The file.dotfile in this directory prevents the rmdir command from removing krsort.dir.new. This file must first be removed before the rmdir command can successfully delete krsort.dir.new.

$ rmdir -i ../krsort.dir.new  ../krsort.dir.new: ? (y/n) y  rmdir: ../krsort.dir.new: Directory not empty  $ rm ../krsort.dir.new/.dotfile  $ rmdir -i ../krsort.dir.new  ../krsort.dir.new: ? (y/n) y  $ 

rmdir has now successfully removed krsort.dir.new because.dotfile is gone, as shown in Figure 3-17:

Figure 3-17. rmdir Removes /home/denise/krsort.dir.new

Manual Pages for Some Commands Used in Chapter 3

The following are the HP-UX manual pages for many of the commands used in the chapter. Commands often differ among UNIX variants, so you may find differences in the options or other areas for some commands; however, the following manual pages serve as an excellent reference.

cd

cd - Change working directory.

     cd(1)                                                           cd(1)  NAME       cd - change working directory  SYNOPSIS       cd [directory]  DESCRIPTION       If directory is not specified, the value of shell parameter HOME is       used as the new working directory. If directory specifies a complete       path starting with /, ., .., directory becomes the new working       directory. If neither case applies, cd tries to find the designated       directory relative to one of the paths specified by the CDPATH shell       variable. CDPATH has the same syntax as, and similar semantics to,       the PATH shell variable. cd must have execute (search) permission in       directory.       cd exists only as a shell built-in command because a new process is       created whenever a command is executed, making cd useless if written       and processed as a normal system command. Moreover, different shells       provide different implementations of cd as a built-in utility.       Features of cd as described here may not be supported by all the       shells. Refer to individual shell manual entries for differences.       If cd is called in a subshell or a separate utility execution       environment such as:            find . -type d -exec cd {}; -exec foo {};            (which invokes foo on accessible directories)       cd does not affect the current directory of the caller's environment.       Another usage of cd as a stand-alone command is to obtain the exit       status of the command.  EXTERNAL INFLUENCES     International Code Set Support       Single- and multi-byte character code sets are supported.  EXAMPLES       Change the current working directory to the HOME directory from any       location in the file system:            cd       Change to new current working directory foo residing in the current       directory:            cd foo       or            cd ./foo       Change to directory foobar residing in the current directory's parent       directory:            cd ../foobar       Change to the directory whose absolute pathname is       /usr/local/lib/work.files:            cd /usr/local/lib/work.files       Change to the directory proj1/schedule/staffing/proposals relative to       home directory:            cd $HOME/proj1/schedule/staffing/proposals  VARIABLES       The following environment variables affect the execution of cd:       HOME                The name of the home directory, used when no                           directory operand is specified.       CDPATH              A colon-separated list of pathnames that refer to                           directories. If the directory operand does not                           begin with a slash (/) character, and the first                           component is not dot or dot-dot, cd searches for                           directory relative to each directory named in the                           CDPATH variable, in the order listed. The new                           working directory is set to the first matching                           directory found. An empty string in place of a                           directory pathname represents the current                           directory. If CDPATH is not set, it is treated as                           if it was an empty string.  RETURN VALUE       Upon completion, cd exits with one of the following values:        0                  The directory was successfully changed.       >0                  An error occurred. The working directory remains                           unchanged.  SEE ALSO       csh(1), pwd(1), ksh(1), sh-posix(1), sh(1), chdir(2).  STANDARDS CONFORMANCE       cd: SVID2, SVID3, XPG2, XPG3, XPG4, POSIX.2 

chmod

chmod - Change permissions.

     chmod(1)                                                          chmod(1)  NAME       chmod - change file mode access permissions  SYNOPSIS       /usr/bin/chmod [-A] [-R] symbolic_mode_list file ...     Obsolescent form:       /usr/bin/chmod [-A] [-R] numeric_mode file ...  DESCRIPTION       The chmod command changes the permissions of one or more files       according to the value of symbolic_mode_list or numeric_mode. You can       display the current permissions for a file with the ls -l command (see       ls(1)).     Symbolic Mode List       A symbolic_mode_list is a comma-separated list of operations in the       following form. Whitespace is not permitted.            [who]op[permission][,...]       The variable fields can have the following values:            who         One or more of the following letters:                             u    Modify permissions for user (owner).                             g    Modify permissions for group.                             o    Modify permissions for others.                             a    Modify permissions for all users (a is                                  equivalent to ugo).            op          Required; one of the following symbols:                             +    Add permission to the existing file mode                                  bits of who.                             -    Delete permission from the existing file                                  mode bits of who.                             =    Replace the existing mode bits of who with                                  permission.            permission One or more of the following letters:                            r    Add or delete the read permission for who.                            w    Add or delete the write permission for who.                           x   Add or delete the execute file (search                               directory) permission for who.                           s   Add or delete the set-owner-id or set-                              group-id on file execution permission for                               who. Useful only if u or g is expressed or                               implied in who.                           t   Add or delete the save-text-image on file                               execution (sticky bit) permission. Useful                               only if u is expressed or implied in who.                               See chmod(2).                           x   Conditionally add or delete the                               execute/search permission as follows:                               -  If file is a directory, add or delete                                  the search permission to the existing                                  file mode for who. (Same as x.)                               -  If file is not a directory, and the                                  current file permissions include the                                  execute permission (ls -l displays an x                                  or an s) for at least one of user,                                  group, or other, then add or delete the                                  execute file permission for who.                               -  If file is not a directory, and no                                  execute permissions are set in the                                  current file mode, then do not change                                  any execute permission.                     Or one only of the following letters:                          u    Copy the current user permissions to who.                          g    Copy the current group permissions to who.                          o    Copy the current other permissions to who.    The operations are performed in the order specified, and can override    preceding operations specified in the same command line.    If who is omitted, the r, w, x, and X permissions are changed for all    users if the changes are permitted by the current file mode creation    mask (see umask(1)). The s and t permissions are changed as if a was    specified in who.    Omitting permission is useful only when used with = to delete all    permissions.  Numeric Mode (Obsolescent)   Absolute permissions can be set by specifying a numeric_mode, an octal   number constructed from the logical OR (sum) of the following mode   bits:   Miscellaneous mode bits:        4000 (= u=s) Set-user-id on file execution (file only)        2000 (= g=s) Set-group-id on file execution        1000 (= u=t) Set sticky bit; see chmod(2)   Permission mode bits:        0400  (= u=r)  Read by owner        0200  (= u=w)  Write by owner        0100  (= u=x)  Execute (search in directory) by owner        0040  (= g=r)  Read by group        0020  (= g=w)  Write by group        0010  (= g=x)  Execute/search by group        0004  (= o=r)  Read by others             0002 (= o=w) Write by others             0001 (= o=x) Execute/search by others      Options             -A  Preserve any optional access control list (ACL) entries                 associated with the file. By default, in conformance with                 the IEEE Standard POSIX 1003.1-1988, optional ACL entries                 are deleted. For information about access control lists,                 see acl(5).             -R  Recursively change the file mode bits. For each file                 operand that names a directory, chmod alters the file mode                 bits of the named directory and all files and subdirectories                 in the file hierarchy below it.       Only the owner of a file, or a user with appropriate privileges, can       change its mode.       Only a user having appropriate privileges can set (or retain, if       previously set) the sticky bit of a regular file.       In order to set the set-group-id on execution bit, the group of the       file must correspond to your current group ID.       If chmod is used on a symbolic link, the mode of the file referred to       by the link is changed.  EXTERNAL INFLUENCES     Environment Variables       LC_MESSAGES determines the language in which messages are displayed.       If LC_MESSAGES is not specified in the environment or is set to the       empty string, the value of LANG is used as a default for each       unspecified or empty variable. If LANG is not specified or is set to       the empty string, a default of "C" (see lang(5)) is used instead of       LANG.       If any internationalization variable contains an invalid setting,       chmod behaves as if all internationalization variables are set to "C".       See environ(5).     International Code Set Support       Single- and multi-byte character code sets are supported.  RETURN VALUE       Upon completion, chmod returns one of the following values:             0 Successful completion.            >0 An error condition occurred.  EXAMPLES       Deny write permission to others:            chmod o-w file       Make a file executable by everybody:            chmod a+x file       Assign read and execute permission to everybody, and set the set-      user-id bit:            chmod a=rx,u+s file       Assign read and write permission to the file owner, and read       permission to everybody else:            chmod u=rw,go=r file       or            chmod 644 file (obsolescent form)       Traverse a directory subtree making all regular files readable by user       and group only, and all executables and directories executable       (searchable) by everyone:            chmod -R ug+r,o-r,a+X pathname       If the current value of umask is 020 (umask -S displays       u=rwx,g=rx,o=rwx; do not change write permission for group) and the       current permissions for file mytest are 444 (a=r), displayed by ls -l       as -r--r--r--, then the command            chmod +w mytest       sets the permissions to 646 (uo=rw,g=r), displayed by ls -l as -rw-r-      -rw-.       If the current value of umask is 020 (umask -S displays       u=rwx,g=rx,o=rwx; do not change write permission for group) and the       current permissions for file mytest are 666 (a=rw), displayed by ls -l       as -rw-rw-rw-, then the command            chmod -w mytest       sets the permissions to 464 (uo=r,g=rw), displayed by ls -l as -r--      rw-r--.  DEPENDENCIES       The -A option causes chmod to fail on file systems that do not support       ACLs.  AUTHOR       chmod was developed by AT&T and HP.  SEE ALSO       chacl(1), ls(1), umask(1), chmod(2), acl(5).  STANDARDS CONFORMANCE       chmod: SVID2, SVID3, XPG2, XPG3, XPG4, POSIX.2 

cp

cp - Copy files and directories.

cp(1)                                                                 cp(1)  NAME       cp - copy files and directory subtrees  SYNOPSIS       cp [-f|-i] [-p] [-e extarg ] file1 new_file       cp [-f|-i] [-p] [-e extarg ] file1 [file2 ...] dest_directory       cp [-f|-i] [-p] [-R|-r] [-e extarg ] directory1 [directory2 ...]       dest_directory  DESCRIPTION       cp copies:            -  file1 to new or existing new_file,            -  file1 to existing dest_directory,            -  file1, file2, ... to existing dest_directory,            -  directory subtree directory1, to new or existing               dest_directory. or            -  multiple directory subtrees directory1, directory2, ... to               new or existing dest_directory.       cp fails if file1 and new_file are the same (be cautious when using       shell metacharacters). When destination is a directory, one or more       files are copied into that directory. If two or more files are       copied, the destination must be a directory. When copying a single       file to a new file, if new_file exists, its contents are destroyed.       If the access permissions of the destination dest_directory or       existing destination file new_file forbid writing, cp aborts and       produces an error message ``cannot create file''.       To copy one or more directory subtrees to another directory, the -r       option is required. The -r option is ignored if used when copying a       file to another file or files to a directory.       If new_file is a link to an existing file with other links, cp       overwrites the existing file and retains all links. If copying a file       to an existing file, cp does not change existing file access       permission bits, owner, or group.       When copying files to a directory or to a new file that does not       already exist, cp creates a new file with the same file permission       bits as file1, modified by the file creation mask of the user if the       -p option was not specified, and then bitwise inclusively ORed with       S_IRWXU. The owner and group of the new file or files are those of       the user. The last modification time of new_file (and last access       time, if new_file did not exist) and the last access time of the       source file1 are set to the time the copy was made.     Options             -i      (interactive copy) Cause cp to write a prompt to standard                     error and wait for a response before copying a file that would                     overwrite an existing file. If the response from the standard                     input is affirmative, the file is copied if permissions allow                     the copy. If the -i (interactive) and -f (forced-copy)                     options are both specified, the -i option is ignored.             -f      Force existing destination pathnames to be removed before                     copying, without prompting for confirmation. This option has                     the effect of destroying and replacing any existing file whose                     name and directory location conflicts with the name and                     location of the new file created by the copy operation.             -p      (preserve permissions) Causes cp to preserve in the copy as                     many of the modification time, access time, file mode, user                     ID, and group ID as allowed by permissions.             -r      (recursive subtree copy) Cause cp to copy the subtree rooted                     at each source directory to dest_directory. If dest_directory                     exists, it must be a directory, in which case cp creates a                     directory within dest_directory with the same name as file1                     and copies the subtree rooted at file1 to                     dest_directory/file1. An error occurs if dest_directory/file1                     already exists. If dest_directory does not exist, cp creates                     it and copies the subtree rooted at file1 to dest_directory.                     Note that cp -r cannot merge subtrees.                     Usually normal files and directories are copied. Character                     special devices, block special devices, network special files,                     named pipes, symbolic links, and sockets are copied, if the                     user has access to the file; otherwise, a warning is printed                     stating that the file cannot be created, and the file is                     skipped.                     dest_directory should not reside within directory1, nor should                     directory1 have a cyclic directory structure, since in both                     cases cp attempts to copy an infinite amount of data.             -R      (recursive subtree copy) The -R option is identical to the -r                     option with the exception that directories copied by the -R                     option are created with read, write, and search permission for                     the owner. User and group permissions remain unchanged.                     With the -R and -r options, in addition to regular files and                     directories, cp also copies FIFOs, character and block device                     files and symbolic links. Only superusers can copy device                     files. All other users get an error. Symbolic links are                     copied so the target points to the same location that the                     source did.                     Warning: While copying a directory tree that has device                     special files, use the -r option; otherwise, an infinite                     amount of data is read from the device special file and is                     duplicated as a special file in the destination directory                     occupying large file system space.             -e extarg                     Specifies the handling of any extent attributes of the file[s]                     to be copied. extarg takes one of the following values.                          warn     Issues a warning message if extent attributes                                   cannot be copied, but copies the file anyway.                          ignore   Does not copy the extent attributes.                          force    Fails to copy the file if the extent attribute                                   can not be copied.               Extent attributes can not be copied if the files are being               copied to a file system which does not support extent               attributes or if that file system has a different block size               than the original. If -e is not specified, the default value               for extarg is warn.     Access Control Lists (ACLs)       If new_file is a new file, or if a new file is created in       dest_directory, it inherits the access control list of the original       file1, file2, etc., altered to reflect any difference in ownership       between the two files (see acl(5)).  EXTERNAL INFLUENCES     Environment Variables       LC_CTYPE determines the interpretation of text as single and/or       multi-byte characters.       LANG and LC_CTYPE determine the local language equivalent of y (for       yes/no queries).       LANG determines the language in which messages are displayed.       If LC_CTYPE is not specified in the environment or is set to the empty       string, the value of LANG is used as a default for each unspecified or       empty variable. If LANG is not specified or is set to the empty       string, a default of "C" (see lang(5)) is used instead of LANG. If       any internationalization variable contains an invalid setting, cp       behaves as if all internationalization variables are set to "C". See       environ(5).     International Code Set Support       Single- and multi-byte character code sets are supported.  EXAMPLES       The following command moves the directory sourcedir and its contents       to a new location (targetdir) in the file system. Since cp creates       the new directory, the destination directory targetdir should not       already exist.            cp -r sourcedir targetdir && rm -rf sourcedir       The -r option copies the subtree (files and subdirectories) in       directory sourcedir to directory targetdir. The double ampersand (&&)       causes a conditional action. If the operation on the left side of the       && is successful, the right side is executed (and removes the old       directory). If the operation on the left of the && is not successful,       the old directory is not removed.       This example is equivalent to:            mv sourcedir targetdir       To copy all files and directory subtrees in the current directory to       an existing targetdir, use:            cp -r * targetdir       To copy all files and directory subtrees in sourcedir to targetdir,       use:            cp -r sourcedir/* targetdir       Note that directory pathnames can precede both sourcedir and       targetdir.       To create a zero-length file, use any of the following:            cat /dev/null >file            cp /dev/null file            touch file  DEPENDENCIES     NFS       Access control lists of networked files are summarized (as returned in       st_mode by stat()), but not copied to the new file. When using mv or       ln on such files, a + is not printed after the mode value when asking       for permission to overwrite a file.  AUTHOR       cp was developed by AT&T, the University of California, Berkeley, and       HP.  SEE ALSO       cpio(1), ln(1), mv(1), rm(1), link(1M), lstat(2), readlink(2),       stat(2), symlink(2), symlink(4), acl(5).  STANDARDS CONFORMANCE       cp: SVID2, SVID3, XPG2, XPG3, XPG4, POSIX.2 

mkdir

mkdir - Make a directory.

mkdir(1)                                                            mkdir(1)  NAME       mkdir - make a directory  SYNOPSIS       mkdir [-p] [-m mode] dirname ...  DESCRIPTION       mkdir creates specified directories in mode 0777 (possibly altered by       umask unless specified otherwise by a -m mode option (see umask(1)).       Standard entries, . (for the directory itself) and .. (for its parent)       are created automatically. If dirname already exists, mkdir exits       with a diagnostic message, and the directory is not changed.     Options       mkdir recognizes the following command-line options:            -m mode        After creating the directory as specified, the                           file permissions are set to mode, which is a                           symbolic mode string as defined for chmod (see                           chmod(1)). The umask(1) has precedence over -m.            -p             Intermediate directories are created as necessary.                           Otherwise, the full path prefix of dirname must                           already exist. mkdir requires write permission in                           the parent directory.                           For each directory name in the pathname prefix of                           the dirname argument that is not the name of an                           existing directory, the specified directory is                           created using the current umask setting, except                           that the equivalent of chmod u+wx is done on each                           component to ensure that mkdir can create lower                           directories regardless of the setting of umask.                           Each directory name in the pathname prefix of the                           dirname argument that matches an existing                           directory is ignored without error. If an                           intermediate path component exists, but has                           permissions set to prevent writing or searching,                           mkdir fails with an error message. If the dirname                           argument (including pathname prefix) names an                           existing directory, mkdir fails with an error                           message.                           If the -m option is used, the directory specified                           by dirname (excluding directories in the pathname                           prefix) is created with the permissions specified                           by mode.       Only LINK_MAX subdirectories can be created (see limits(5)).  EXTERNAL INFLUENCES     Environment Variables       LANG provides a default value for the internationalization variables       that are unset or null. If LANG is unset or null, the default value of       "C" (see lang(5)) is used. If any of the internationalization       variables contains an invalid setting, mkdir will behave as if all       internationalization variables are set to "C". See environ(5).       LC_ALL If set to a non-empty string value, overrides the values of all       the other internationalization variables.       LC_CTYPE determines the interpretation of text as single and/or       multi-byte characters, the classification of characters as printable,       and the characters matched by character class expressions in regular       expressions.       LC_MESSAGES determines the locale that should be used to affect the       format and contents of diagnostic messages written to standard error       and informative messages written to standard output.       NLSPATH determines the location of message catalogues for the       processing of LC_MESSAGES.     International Code Set Support       Single- and multi-byte character code sets are supported.  DIAGNOSTICS       mkdir returns exit code 0 if all directories were successfully made.       Otherwise, it prints a diagnostic and returns non-zero.  EXAMPLES       Create directory gem beneath existing directory raw in the current       directory:            mkdir raw/gem       Create directory path raw/gem/diamond underneath the current directory       and set permissions on directory diamond to read-only for all users       (a=r):            mkdir -p -m "a=r" raw/gem/diamond       which is equivalent to (see chmod(1)):            mkdir -p -m 444 raw/gem/diamond       If directories raw or raw and gem already exist, only the missing       directories in the specified path are created.  SEE ALSO       rm(1), sh(1), umask(1).  STANDARDS CONFORMANCE       mkdir: SVID2, SVID3, XPG2, XPG3, XPG4, POSIX.2 

mv

mv - Move or rename files and directories.

     mv(1)                                                          mv(1)  NAME       mv - move or rename files and directories  SYNOPSIS       mv [-f|-i] [-e extarg] file1 new-file       mv [-f|-i] [-e extarg] file1 [file2 ...] dest-directory       mv [-f|-i] [-e extarg] directory1 [directory2 ...] dest-directory  DESCRIPTION       The mv command moves:            -  One file (file1) to a new or existing file (new-file).            -  One or more files (file1, [file2, ...]) to an existing               directory (dest-directory).            -  One or more directory subtrees (directory1, [directory2, ...])               to a new or existing directory (dest-directory).       Moving file1 to new-file is used to rename a file within a directory       or to relocate a file within a file system or across different file       systems. When the destination is a directory, one or more files are       moved into that directory. If two or more files are moved, the       destination must be a directory. When moving a single file to a new       file, if new-file exists, its contents are destroyed.       If the access permissions of the destination dest-directory or       existing destination file new-file forbid writing, mv asks permission       to overwrite the file. This is done by printing the mode (see       chmod(2) and Access Control Lists below), followed by the first       letters of the words yes and no in the language of the current locale,       prompting for a response, and reading one line from the standard       input. If the response is affirmative and the action is permissible,       the operation occurs; if not, the command proceeds to the next source       file, if any.       If file1 is a file and new-file is a link to another file with other       links, the other links remain and new-file becomes a new file. If       file1 is a file with links or a link to a file, the existing file or       link remains intact, but the name is changed to new-file which may or       may not be in the directory where file1 resided, depending on       directory path names used in the mv command. The last access and       modification times of the file or files being moved remain unchanged.     Options       mv recognizes the following options:            -f             Perform mv commands without prompting for                           permission. This option is assumed when the                           standard input is not a terminal.                   -i      Causes mv to write a prompt to standard output                           before moving a file that would overwrite an                           existing file. If the response from the standard                           input is affirmative, the file is moved if                           permissions allow the move.                   -e      extarg Specifies the handling of any extent attributes of                           the files(s) to be moved. extarg can be one of                           the following values:                                warn        Issue a warning message if extent                                            attributes cannot be preserved,                                            but move the file anyway.                                ignore      Do not preserve extent                                            attributes.                                force       Do not move the file if the                                            extent attributes cannot be                                            preserved.                                            If multiple source files are                                            specified with a single target                                            directory, mv will move the files                                            that either do not have extent                                            attributes or that have extent                                            attributes that can be preserved.                                            mv will not move the files if it                                            cannot preserve their extent                                            attributes.                                Extent attributes cannot be preserved if the                                files are being moved to a file system that                                does not support extent attributes or if that                                file system has a different block size than                                the original. If -e is not specified, the                                default value for extarg is warn.     Access Control Lists (ACLs)       If optional ACL entries are associated with new-file, mv displays a       plus sign (+) after the access mode when asking permission to       overwrite the file.       If new-file is a new file, it inherits the access control list of       file1, altered to reflect any difference in ownership between the two       files (see acl(5)).  EXTERNAL INFLUENCES     Environment Variables       LC_CTYPE determines the interpretation of text as single byte and/or       multibyte characters.       LANG and LC_CTYPE determine the local language equivalent of y (for       yes/no queries).       LANG determines the language in which messages are displayed.       If LC_CTYPE is not specified in the environment or is set to the empty       string, the value of LANG is used as a default for each unspecified or       empty variable. If LANG is not specified or is set to the empty       string, a default of C (see lang(5)) is used instead of LANG. If any       internationalization variable contains an invalid setting, mv behaves       as if all internationalization variables are set to C. See       environ(5).     International Code Set Support       Single character and multibyte character code sets are supported.  EXAMPLES       Rename a file in the current directory:            mv old-filename new-filename       Rename a directory in the current directory:            mv old-dirname new-dirname       Rename a file in the current directory whose name starts with a       nonprinting control character or a character that is special to the       shell, such as - and * (extra care may be required depending on the       situation):            mv ./bad-filename new-filename            mv ./?bad-filename new-filename            mv ./*bad-filename new-filename       Move directory sourcedir and its contents to a new location       (targetdir) in the file system (upon completion, a subdirectory named       sourcedir resides in directory targetdir):            mv sourcedir targetdir       Move all files and directories (including links) in the current       directory to a new location underneath targetdir:            mv * targetdir       Move all files and directories (including links) in sourcedir to a new       location underneath targetdir (sourcedir and targetdir are in separate       directory paths):            mv sourcedir/* targetdir  WARNINGS       If file1 and new-file exist on different file systems, mv copies the       file and deletes the original. In this case the mover becomes the       owner and any linking relationship with other files is lost. mv       cannot carry hard links across file systems. If file1 is a directory,       mv copies the entire directory structure onto the destination file       system and deletes the original.       mv cannot be used to perform the following operations:            -  Rename either the current working directory or its parent               directory using the . or .. notation.            -  Rename a directory to a new name identical to the name of a               file contained in the same parent directory.  DEPENDENCIES     NFS       Access control lists of networked files are summarized (as returned in       st_mode by stat(2)), but not copied to the new file. When using mv on       such files,a +isnotprinted after the mode value when asking for       permission to overwrite a file.  AUTHOR       mv was developed by AT&T, the University of California, Berkeley and       HP.  SEE ALSO       cp(1), cpio(1), ln(1), rm(1), link(1M), lstat(2), readlink(2),       stat(2), symlink(2), symlink(4), acl(5).  STANDARDS CONFORMANCE       mv: SVID2, SVID3, XPG2, XPG3, XPG4, POSIX.2 

pwd

pwd - Present working directory name.

     pwd(1)                                                    pwd(1)  NAME       pwd - working directory name  SYNOPSIS       pwd  DESCRIPTION       pwd prints the path name of the working (current) directory.  EXTERNAL INFLUENCES     Environment Variables       LC_MESSAGES determines the language in which messages are displayed.       If LC_MESSAGES is not specified in the environment or is set to the       empty string, the value of LANG is used as a default for each       unspecified or empty variable. If LANG is not specified or is set to       the empty string, a default of "C" (see lang(5)) is used instead of       LANG.       If any internationalization variable contains an invalid setting, pwd       behaves as if all internationalization variables are set to "C". See       environ(5).     International Code Set Support       Single- and multi-byte character code sets are supported.  DIAGNOSTICS       Cannot open ..       Read error in ..               Possible file system trouble; contact system administrator.       pwd: cannot access parent directories               Current directory has been removed (usually by a different               process). Use cd command to move to a valid directory (see               cd(1)).  EXAMPLES       This command lists the path of the current working directory. If your       home directory were /mnt/staff and the command cd camp/nevada were       executed from the home directory, typing pwd would produce the       following:            /mnt/staff/camp/nevada  AUTHOR       pwd was developed by AT&T and HP.  SEE ALSO       cd(1).  STANDARDS CONFORMANCE       pwd: SVID2, SVID3, XPG2, XPG3, XPG4, POSIX.2 

rm

rm - Remove files or directories.

rm(1)                                                        rm(1)  NAME       rm - remove files or directories  SYNOPSIS       rm [-f|-i] [-Rr] file ...  DESCRIPTION       The rm command removes the entries for one or more files from a       directory. If an entry was the last link to the file, the file is       destroyed. Removal of a file requires write and search (execute)       permission in its directory, but no permissions on the file itself.       However, if the sticky bit is set on the directory containing the       file, only the owner of the file, the owner of the directory, or a       user having appropriate privileges can remove the file.       If a user does not have write permission for a file to be removed and       standard input is a terminal, a prompt containing the file name and       its permissions is printed requesting that the removal of the file be       confirmed (see Access Control Lists below). A line is then read from       standard input. If that line begins with y the file is deleted;       otherwise, the file remains. No questions are asked when the -f       option is given or if standard input is not a terminal.       If file is of type directory, and the -f option is not specified, and       either the permissions of file do not permit writing and standard       input is a terminal or the -i option is specified, rm writes a prompt       to standard error and reads a line from standard input. If the       response does not begin with y, it does nothing more with the current       file and goes on to any remaining files.     Options       rm recognizes the following options:            -f   Force each file or directory to be removed without prompting                 for confirmation, regardless of the permissions of the                 entry. This option also suppresses diagnostic messages                 regarding nonexistent operands.                 This option does not suppress any diagnostic messages other                 than those regarding nonexistent operands. To suppress all                 error message and interactive prompts, the -f option should                 be used while redirecting standard error output to                 /dev/null.                 This option ignores any previous occurrence of the -i                 option.            -i   Write a prompt to standard error requesting confirmation                 before removing each entry.               This option ignores any previous occurrence of the -f               option.          -R   For each argument that is a directory, this option causes rm               to recursively delete the entire contents of that directory               before removing the directory itself. When used in               conjunction with the -i option, rm asks whether to examine               each directory before interactively removing files in that               directory and again afterward to confirm removing the               directory itself.               The -R option will descend to arbitrary depths in a file               hierarchy and will not fail due to path length limitations               unless the length of file name, file specified by the user               exceeds system limitations.          -r   Equivalent to -R.     Access Control Lists       If a file has optional ACL entries, rm displays a plus sign (+) after       the file's permissions. The permissions shown summarize the file's       st_mode value returned by stat() (see stat(2)). See also acl(5).  EXTERNAL INFLUENCES     Environment Variables       LANG provides a default value for the internationalization variables       that are unset or null. If LANG is unset or null, the default value of       "C" (see lang(5)) is used. If any of the internationalization       variables contains an invalid setting, rm will behave as if all       internationalization variables are set to "C". See environ(5).       LC_ALL If set to a non-empty string value, overrides the values of all       the other internationalization variables.       LC_CTYPE determines the interpretation of file names as single and/or       multi-byte characters, the classification of characters as printable,       and the characters matched by character class expressions in regular       expressions.       LC_MESSAGES determines the locale that should be used to affect the       format and contents of diagnostic messages written to standard error       and informative messages written to standard output.       NLSPATH determines the location of message catalogues for the       processing of LC_MESSAGES.     International Code Set Support       Single- and multibyte character code sets are supported.  DIAGNOSTICS       Generally self-explanatory. Note that the -f option does not suppress       all diagnostic messages.       It is forbidden to remove the file .., in order to avoid the       consequences of using a command such as:            rm -r .*       If a designated file is a directory, an error comment is printed       unless the -R or -r option is used.  EXAMPLES       Remove files with a prompt for verification:            rm -i file1 file2       Remove all the files in a directory:            rm -i mydirectory/*       Note that the previous command removes files only, and does not remove       any directories in mydirectory.       Remove a file in the current directory whose name starts with - or *       or some other character that is special to the shell:            rm ./-filename            rm \*filename            etc.       Remove a file in the current directory whose name starts with some       strange (usually nonprinting, invisible) character or perhaps has       spaces at the beginning or end of the filename, prompting for       confirmation:            rm -i *filename*       If *filename* is not unique in the directory, enter n when each of the       other files is prompted.       A powerful and dangerous command to remove a directory is:            rm -fR directoryname       or            rm -Rf directoryname       which removes all files and directories from directoryname without any       prompting for verification to remove the files or the directories.       This command should only be used when you are absolutely certain that       all the files and directories in directoryname as well as       directoryname itself are to be removed.  DEPENDENCIES     NFS       rm does not display a plus sign (+) to indicate the existence of       optional access control list entries when asking for confirmation       before removing a networked file.  SEE ALSO       rmdir(1), unlink(2), acl(5).  STANDARDS CONFORMANCE       rm: SVID2, SVID3, XPG2, XPG3, XPG4, POSIX.2 

rmdir

rmdir - Remove directories.

rmdir(1)                                                                 rmdir(1)  NAME       rmdir - remove directories  SYNOPSIS       rmdir [-f|-i] [-p] dir ...  DESCRIPTION       rmdir removes the directory entry for each dir operand that refers to       an empty directory.       Directories are removed in the order specified. Consequently, if a       directory and a subdirectory of that directory are both specified as       arguments, the subdirectory must be specified before the parent       directory so that the parent directory will be empty when rmdir tries       to remove it. Removal of a directory requires write and search       (execute) permission in its parent directory, but no permissions on       the directory itself; but if the sticky bit is set on the parent       directory, only the owner of the directory, the owner of the parent       directory, or a user having appropriate privileges can remove the       directory.     Options       rmdir recognizes the following options:            -f   Force each directory to be removed without prompting for                 confirmation, regardless of the presence of the -i option.                 This option also suppresses diagnostic messages regarding                 non-existent operands.                 This option does not suppress any diagnostic messages other                 than those regarding non-existent operands. To suppress all                 error message and interactive prompts, the -f option should                 be used while redirecting the standard error output to                 /dev/null.                 This option ignores any previous occurrence of the -i                 option.            -i   Write a prompt to the standard error output requesting                 confirmation before removing each directory.                 This option ignores any previous occurrence of the -f                 option.            -p   Path removal. If, after removing a directory with more than                 one pathname component, the parent directory of that                 directory is now empty, rmdir removes the empty parent                 directory. This continues until rmdir encounters a non                empty parent directory, or until all components of the                 original pathname have been removed.                 When used in conjunction with the -i option, rmdir asks                 whether to remove each directory component of a path.  EXTERNAL INFLUENCES     Environment Variables       LANG provides a default value for the internationalization variables       that are unset or null. If LANG is unset or null, the default value of       "C" (see lang(5)) is used. If any of the internationalization       variables contains an invalid setting, rmdir will behave as if all       internationalization variables are set to "C". See environ(5).       LC_ALL If set to a non-empty string value, overrides the values of all       the other internationalization variables.       LC_CTYPE determines the interpretation of dir names as single and/or       multi-byte characters, the classification of characters as printable,       and the characters matched by character class expressions in regular       expressions.       LC_MESSAGES determines the locale that should be used to affect the       format and contents of diagnostic messages written to standard error       and informative messages written to standard output.       NLSPATH determines the location of message catalogues for the       processing of LC_MESSAGES.     International Code Set Support       Single- and multi-byte character code sets are supported.  DIAGNOSTICS       Generally self-explanatory. Note that the -f option does not suppress       all diagnostic messages.  EXAMPLES       To remove directories with a prompt for verification:            rmdir -i directories       To remove as much as possible of a path, type:            rmdir -p component1/component2/dir  SEE ALSO        rm(1), rmdir(2), stat(2).  STANDARDS CONFORMANCE       rmdir: SVID2, XPG2, XPG3, XPG4 

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