set

Set or unset values of shell options and positional parameters.

Using + rather than - causes these flags to be turned off.

Documentation

• The Set Builtin [EN] @ GNU Bash Reference Manual

• bash -c 'help set'
• man 1 'bash' [EN]])

Further Information

• Use the Unofficial Bash Strict Mode (Unless You Looove Debugging) [EN] @ aaron maxwell

Syntax

set [PARAMETER ...] [ARGUMENT ...]

Parameters

-e

Exit immediately if a command exits with a non-zero status.

-f

Disable file name generation (globbing).

-o NAME

Set the variable corresponding to NAME:

errexit

Same as -e.

noglob

Same as -f.

nounset

Same as -u.

pipefail

The return value of a pipeline is the status of the last command to exit with a non-zero status, or zero if no command exited with a non-zero status.

verbose

Same as -v.

xtrace

Same as -x.

-u

Treat unset variables as an error when substituting.

-v

Print shell input lines as they are read.

-x

Print commands and their arguments as they are executed.

Examples

Start of a Bash script

#!/bin/bash -

Start of a Bash script in an unofficial 'Strict Mode'

#!/bin/bash -
set -o 'errexit' -o 'noglob' -o 'nounset' -o 'pipefail'
IFS=$'\t\n'

Show the value of some shell options

set -o | grep --regexp='^h'

Output:

hashall        	on
histexpand     	on
history        	on