Bash:ScriptExamples - Revision history

Hdridder at 10:06, 14 August 2025

2025-08-14T10:06:11Z

← Older revision		Revision as of 10:06, 14 August 2025
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	When the block contains calls to external systems (remsh, ssh) this call swallows all input and consequently the loop is ended. This can be prevented by assigning specific input to the call (e.g. ssh user@system command < /dev/null		When the block contains calls to external systems (remsh, ssh) this call swallows all input and consequently the loop is ended. This can be prevented by assigning specific input to the call (e.g. ssh user@system command < /dev/null

			=Blocks=
			You can create blocks of code by putting () or {} around the commands. Can be handy to redirect all output of a block.

			() creates a subshell, variables set in the subshell will not be available outside the block.

			{} executes the block in the same context, variables set in the block are available outside the block too.

	=Check interactive shell=		=Check interactive shell=

Hdridder at 20:30, 3 August 2025

2025-08-03T20:30:38Z

← Older revision		Revision as of 20:30, 3 August 2025
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	[[Category:Linux/Unix]]		[[Category:Linux/Unix]]
			=Control structures=

	=~~Control structures=~~		;if
			<syntaxhighlight lang=bash>
			if <conditions>
			then
			<block>
			elif <conditions>
			then
			<block>
			else
			<block>
			fi
			</syntaxhighlight>

	;<~~code~~><~~nowiki~~>~~if conditions then~~ ~~[[ block ]] else [[~~ block ~~]] fi</nowiki~~></~~code~~>		;while
	~~:Generic if statement~~		<syntaxhighlight lang=bash>
			while <conditions>
			do
			<block>
			done
			</syntaxhighlight>

	==conditions==		==conditions==
Line 14:		Line 31:

	To have multiple conditions use && or \|\| for and and or		To have multiple conditions use && or \|\| for and and or

			==while caveat==
			When the block contains calls to external systems (remsh, ssh) this call swallows all input and consequently the loop is ended. This can be prevented by assigning specific input to the call (e.g. ssh user@system command < /dev/null


	=Check interactive shell=		=Check interactive shell=

Hdridder at 06:43, 4 January 2025

2025-01-04T06:43:48Z

← Older revision		Revision as of 06:43, 4 January 2025
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	[[Category:Linux/Unix]]		[[Category:Linux/Unix]]

			=Control structures=

			;<code><nowiki>if conditions then [[ block ]] else [[ block ]] fi</nowiki></code>
			:Generic if statement

			==conditions==
			In the if statement a condition is true if the exit code ($?) is 0 else it is false.

			So the condition can be any statement. If the statement may have output you can redirect that to /dev/null.

			The [[bash:Test\|test]] statement can be used to test variables

			To have multiple conditions use && or \|\| for and and or

	=Check interactive shell=		=Check interactive shell=

Hdridder at 09:40, 20 January 2022

2022-01-20T09:40:29Z

← Older revision		Revision as of 09:40, 20 January 2022
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	[[Category:~~Bash~~]]		[[Category:Linux/Unix]]

	=Check interactive shell=		=Check interactive shell=

Hdridder: Created page with "Category:Bash =Check interactive shell= To check within a startup script (like .bashrc) whether or not Bash is running interactively. Test if $- has an 'i' in it or if $P..."

2019-03-15T07:57:02Z

Created page with "Category:Bash =Check interactive shell= To check within a startup script (like .bashrc) whether or not Bash is running interactively. Test if $- has an 'i' in it or if $P..."

New page

[[Category:Bash]]

=Check interactive shell=
To check within a startup script (like .bashrc) whether or not Bash is running interactively. Test if $- has an 'i' in it or if $PS1 (the prompt) exists.

<syntaxhighlight lang=bash>
case "$-" in
*i*) echo This shell is interactive ;;
*) echo This shell is not interactive ;;
esac

if [ -z "$PS1" ]; then
echo This shell is not interactive
else
echo This shell is interactive
</syntaxhighlight>