Section 1.2. Beginner s Guide

1.2. Beginner's Guide

If you're just beginning to work on a Unix system, the abundance of commands might prove daunting. To help orient you, the following lists present a small sampling of commands on various topics.

1.2.1. Communication

Command	Use
ftp	File transfer protocol.
login	Sign on to Unix.
mailx	Read or send mail.
rlogin	Sign on to remote Unix.
talk	Write to other terminals.
telnet	Connect to another system.
vacation	Respond to mail automatically.

1.2.2. Comparisons

Command	Use
cmp	Compare two files, byte by byte.
comm	Compare items in two sorted files.
diff	Compare two files, line by line.
diff3	Compare three files.
sdiff	Compare two files, side by side.

1.2.3. File Management

Command	Use
cat	Concatenate files or display them.
cd	Change directory.
chmod	Change access modes on files.
cp	Copy files.
csplit	Break files at specific locations.
file	Determine a file's type.
head	Show the first few lines of a file.
ln	Create filename aliases.
ls	List files or directories.
mkdir	Create a directory.
more	Display files by screenful.
mv	Move or rename files or directories.
pwd	Print working directory.
rcp	Copy files to remote system.
rm	Remove files.
rmdir	Remove directories.
split	Split files evenly.
tail	Show the last few lines of a file.
wc	Count lines, words, and characters .

1.2.4. Printing

Command	Use
at_cho_prn	Allows you to choose an AppleTalk printer.
cancel	Cancel a printer request.
Enscript	Converts text files to PostScript.
lp	Send to the printer.
lpoptions	Display a list of printer options and defaults.
lprm	Cancel a print request.
lpstat	Get printer status.
pr	Format and paginate for printing .

1.2.5. Programming

Command	Use
cc	C compiler.
ctags	C function references (for vi ).
ld	Loader.
lex	Lexical analyzer generator.
make	Execute commands in a specified order.
od	Dump input in various formats.
strip	Remove data from an object file.
yacc	Parser generator. Can be used with lex .

1.2.6. Searching

Command	Use
egrep	Extended version of grep .
fgrep	Search files for literal words.
find	Search the system for filenames.
grep	Search files for text patterns.
strings	Search binary files for text patterns.

1.2.7. Shell Programming

Command	Use
echo	Repeat command-line arguments on the output.
expr	Perform arithmetic and comparisons.
printf	Format and print command-line arguments.
sleep	Pause during processing.
test	Test a condition.

1.2.8. Storage

Command	Use
compress	Compress files to free up space.
cpio	Copy archives in or out.
gunzip	Expand compressed ( .gz and .Z ) files (preferred).
gzcat	Display contents of compressed files (may be linked to zcat ).
gzip	Compress files to free up space (preferred).
tar	Tape archiver.
uncompress	Expand compressed ( .Z ) files.
zcat	Display contents of compressed files.

1.2.9. System Status

Command	Use
at	Execute commands later.
atq	Show jobs queued by at .
atrm	Remove job queued by at .
chgrp	Change file group .
chown	Change file owner.
crontab	Automate commands.
date	Display or set date.
df	Show free disk space.
du	Show disk usage.
env	Show environment variables .
finger	Display information about users.
kill	Terminate a running command.
printenv	Show environment variables.
ps	Show processes.
stty	Set or display terminal settings.
who	Show who is logged in.

1.2.10. Text Processing

Command	Use
col	Process control characters.
cut	Select columns for display.
emacs	Work environment with powerful text editing capabilities.
ex	Line editor underlying vi .
expand	Convert tabs to spaces.
fmt	Produce roughly uniform line lengths.
fold	Break lines.
groff	Format troff input.
join	Merge different columns into a database.
paste	Merge columns or switch order.
rev	Print lines in reverse.
sed	Noninteractive text editor.
sort	Sort or merge files.
tr	Translate (redefine) characters.
uniq	Find repeated or unique lines in a file.
vi	Visual text editor.
xargs	Process many arguments in manageable portions.

1.2.11. Miscellaneous

Command	Use
banner	Make posters from words.
bc	Arbitrary precision calculator.
cal	Display calendar.
clear	Clear the screen.
man	Get information on a command.
nice	Reduce a job's priority.
nohup	Preserve a running job after logging out.
passwd	Set your login password.
script	Produce a transcript of your login session.
su	Become a superuser.
tee	Simultaneously store output in file and send to screen.
which	Print pathname of a command.