Built-In Commands and Reserved Words

B.2 Built-In Commands and Reserved Words

Table 2.3 shows a summary of all built-in commands and reserved words.

Table B.3. Commands and Reserved Words

Command

Chapter

Summary

!

5

Reserved word. Logical NOT of a command exit status.

:

7

Do nothing (just do expansions of any arguments).

.

4

Read file and execute its contents in current shell.

alias

3

Set up shorthand for command or command line.

bg

8

Put job in background.

bind

2

Bind a key sequence to a readline function or macro.

break

5

Exit from surrounding for , select , while , or until loop.

builtin

5

Execute the specified shell built-in.

case

5

Reserved word. Multi-way conditional construct.

cd

1

Change working directory.

command

7

Run a command bypassing shell function lookup.

continue

 

Skip to next iteration of for , select , while , or until loop.

declare

6

Declare variables and give them attributes.

dirs

6

Display the list of currently remembered directories.

disown

8

Remove a job from the job table.

do

5

Reserved word. Part of a for , select , while , or until looping construct.

done

5

Reserved word. Part of a for , select , while , or until looping construct.

echo

4

Expand and print any arguments.

elif

5

Reserved word. Part of an if construct.

else

5

Reserved word. Part of an if construct.

enable

7

Enable and disable built-in shell commands.

esac

5

Reserved word. Part of a case construct.

eval

7

Run the given arguments through command-line processing.

exec

9

Replace the shell with the given program.

exit

5

Exit from the shell.

export

3

Create environment variables.

fc

2

Fix command (edit history file).

fg

8

Put background job in foreground.

fi

5

Reserved word. Part of an if construct.

for

5

Reserved word. Looping construct.

function

4

Define a function.

getopts

6

Process command-line options.

hash

3

Full pathnames are determined and remembered.

help

1

Display helpful information on built-in commands.

history

1

Display command history.

if

5

Reserved word. Conditional construct.

in

5

Reserved word. Part of a case construct.

jobs

1

List any background jobs.

kill

8

Send a signal to a process.

let

6

Arithmetic variable assignment.

local

4

Create a local variable.

logout

1

Exits a login shell.

popd

4

Removes a directory from the directory stack.

pushd

4

Adds a directory to the directory stack.

pwd

1

Print the working directory.

read

7

Read a line from standard input.

readonly

6

Make variables read-only (unassignable).

return

5

Return from the surrounding function or script.

select

5

Reserved word. Menu-generation construct.

set

3

Set options.

shift

6

Shift command-line arguments.

suspend

 

Suspend execution of a shell.

test

5

Evaluates a conditional expression.

then

5

Reserved word. Part of an if construct.

time

 

Reserved word. Run command pipeline and print execution times. The format of the output can be controlled with TIMEFORMAT .

times

 

Print the accumulated user and system times for processes run from the shell.

trap

8

Set up a signal-catching routine.

type

3

Identify the source of a command.

typeset

6

Declare variables and give them attributes. Same as declare .

ulimit

10

Set/show process resource limits.

umask

10

Set/show file permission mask.

unalias

3

Remove alias definitions.

unset

3

Remove definitions of variables or functions.

until

5

Reserved word. Looping construct.

wait

8

Wait for background job(s) to finish.

while

5

Reserved word. Looping construct.

 



Learning the Bash Shell
Learning the bash Shell: Unix Shell Programming (In a Nutshell (OReilly))
ISBN: 0596009658
EAN: 2147483647
Year: 1998
Pages: 104

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