ESC

csh

Filename completion.

Section 28.6

RETURN

csh, sh

Execute command.

space

csh, sh

Argument separator.

TAB

csh, sh

Argument separator.

TAB

bash

Completion (in interactive shells).

Section 28.6

#

csh, sh

Start a comment.

Section 35.1

`

csh, sh

Command substitution (backquotes).

Section 28.14

"

sh

Weak quotes.

Section 27.12

"

csh

Weak quotes.

Section 27.13

$var

csh, sh

Expand variable var.

Section 35.3, Section 35.9

${var}

csh, sh

Same as $var.

Section 35.9

$var:mod

csh

Edit var with modifier mod

Section 28.5

${var-default}

sh

If var not set, use default.

Section 36.7

${var:-default}

bash

If var not set or null, use default.

Section 36.7

${var=default}

sh

If var not set, set it to default and use that value.

Section 36.7

${var:=default}

bash

If var not set or null, set it to default and use that value.

Section 36.7

${var+instead}

sh

If var set, use instead. Otherwise, null string.

Section 36.7

${var:+instead}

bash

If var set or not null, use instead. Otherwise, null string.

Section 36.7

${var?message}

sh

If var set, use its value. Else print message (or default) and exit.

Section 36.7

${var:?message}

bash

If var set or not null, use its value. Else print message (or default) and exit.

Section 36.7

${var#pat}

ksh, bash

Value of var with smallest pat deleted from start.

${var##pat}

ksh, bash

Value of var with largest pat deleted from start.

${var%pat}

ksh, bash

Value of var with smallest pat deleted from end.

${var%%pat}

ksh, bash

Value of var with largest pat deleted from end.

${^array}

zsh

Expand array in place, like rc_expand_param option.

Section 35.9

${=spec}

zsh

Turn on sh_word_split option while evaluating spec.

Section 35.9

${~array}

zsh

Turn on glob_subst option while evaluating spec.

Section 35.9

|

csh, sh

Pipe standard output.

Section 1.5, Section 43.1

|&

csh

Pipe standard output and standard error.

Section 43.5

|&

ksh

Coroutine.

Section 24.4

^

sh only

Pipe character (obsolete).

^

csh, bash

Edit previous command line.

Section 30.5

&

csh, sh

Run program in background.

Section 23.2

&!

zsh

Run program in background without job control.

Section 23.11

&|

zsh

Run program in background without job control.

Section 23.11

?

csh, sh

Match one character.

Section 1.13, Section 33.2

*

csh, sh

Match zero or more characters.

Section 1.13, Section 33.2

;

csh, sh

Command separator.

;;

sh

End of case element.

Section 35.10

~

csh, ksh, bash

Home directory.

Section 31.11

~user

csh, ksh, bash

Home directory of user.

Section 31.11

!

csh, bash

Command history.

Section 30.2

!

bash, ksh93, zsh

Toggle exit status.

Section 35.12

-

zsh

Make a login shell.

Section 3.19

=

csh, sh

Assignment.

Section 35.9,

$#

csh, sh

Number of shell arguments or words in an array.

Section 35.20,

"$@"

sh

Original script arguments.

Section 35.20

$*

csh, sh

Original script arguments, broken into words.

Section 35.20

$?

sh

Status of previous command.

Section 35.12

$$

csh, sh

Process identification number.

Section 27.12

$!

sh

Process identification number of last background job.

Section 4.15

$<

csh

Read input from terminal.

Section 28.9

$_

bash, ksh, zsh

Last argument of previous command.

$n

sh

Argument n. 1 <= n <= 9 for most shells; bash and ksh93 support ${n} for n >= 10.

$0

sh

Name of the shell or shell script.

cmd1 && cmd2

csh, sh

Execute cmd2 if cmd1 succeeds.

Section 35.14

cmd1 || cmd2

csh, sh

Execute cmd2 if cmd1 fails.

Section 35.14

$(..)

ksh, bash

Command substitution.

Section 36.24, Section 28.14

. file

sh

Execute commands from file in this shell.

Section 35.29

:

sh

Evaluate arguments, return true.

Section 35.6

:

sh

Separate values in paths.

Section 31.5, Section 35.6

:

csh

Variable modifier.

Section 28.5

[ ]

csh, sh

Match range of characters.

Section 1.13, Section 33.2

[ ]

sh

Test.

Section 35.26

%n

csh, ksh, bash, zsh

Job number n.

Section 23.3

(cmd;cmd)

csh, sh

Run cmd;cmd in a subshell.

Section 43.7

{ }

csh, bash

In-line expansions.

Section 28.4

>file

csh, sh

Redirect standard output.

Section 43.1

>! file

csh

Output to file, even if noclobber set and file exists.

Section 43.6

>| file

ksh, bash

Output to file, even if noclobber set and file exists.

Section 43.6

>>file

csh, sh

Append standard output.

Section 43.1

>>! file

csh

Append to file, even if noclobber set and file doesn't exist.

Section 43.6

<file

csh, sh

Redirect standard input.

Section 43.1

<<word

csh, sh

Read until word, do command and variable substitution.

Section 27.16, Section 28.13

<<\word

csh, sh

Read until word, no substitution.

Section 27.16

<<-word

sh

Read until word, ignoring leading TABs.

Section 27.16

<> file

ksh, bash, zsh

Open file for writing and reading.

>& file

csh, bash

Redirect standard output and standard error to file.

Section 43.5

m> file

sh

Redirect output file descriptor m to file.

Section 36.16

m>> file

sh

Append output file descriptor m to file.

m< file

sh

Redirect input file descriptor m from file.

<&m

sh

Take standard input from file descriptor m.

>&m

sh

Use file descriptor m as standard output.

Section 36.16

>& -

sh

Close standard output.

Section 36.16

m<& -

sh

Close input file descriptor m.

Section 36.16

n>&m

sh

Connect output file descriptor n to file descriptor m.

Section 36.16

m>& -

sh

Close output file descriptor m.

Section 36.16