Bash:Variables - Revision history

Hdridder: /* Operations on variables */

2022-04-11T18:49:11Z

Operations on variables

← Older revision		Revision as of 18:49, 11 April 2022
Line 81:		Line 81:
	;${#var}		;${#var}
	:Length of the string		:Length of the string

			;Check if a string is in the variable
			The trick is that if the variable does not have the searchstring the variable will be unchanged.
			<syntaxhighlight lang=bash>
			if [ "${var#*searchstring}" != "${var}" ]
			then
			echo "searchstring is in $var"
			fi
			</syntaxhighlight>

2022-04-11T18:14:29Z

← Older revision		Revision as of 18:14, 11 April 2022
Line 62:		Line 62:
	done		done
	</syntaxhighlight>		</syntaxhighlight>

			=Operations on variables=
			* # searches from the beginning
			* % searches from the end

			;${var#??}
			:Remove the first 2 chars
			;${var%??}
			:Remove the last 2 chars
			;${var%e*}
			:Remove everything from and including the last 'e'
			;${var#*e}
			:Remove everything up to the first 'e'
			;${var#* * }
			:Remove the first 2 words from a line (carefully check the spaces)
			;${var% * *}
			:Remove the last 2 words from a line (carefully check the spaces)
			;${#var}
			:Length of the string

2022-01-20T09:40:58Z

2019-08-28T09:41:40Z

Arithmetics

2019-06-12T08:05:06Z

← Older revision		Revision as of 08:05, 12 June 2019
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	[[Category:Bash]]		[[Category:Bash]]
			[[Category:Linux/Unix]]

	=Arithmetics=		=Arithmetics=
Line 40:		Line 41:
	=Nested variables=		=Nested variables=
	;var2=${!var1}		;var2=${!var1}
	:var2 will get the value of the evaluation of var1		:var2 will get the value of the evaluation of var1 (value of var0)
	<syntaxhighlight lang=bash>		<syntaxhighlight lang=bash>
	var0=1		var0=1

2019-06-04T07:15:58Z

@@ Line 37: / Line 37: @@
 ;$!
 :ProcessID of last spawned process.
 =Loop over a range=

2019-04-19T18:30:59Z

← Older revision		Revision as of 18:30, 19 April 2019
Line 37:		Line 37:
	;$!		;$!
	:ProcessID of last spawned process.		:ProcessID of last spawned process.

			=Loop over a range=
			<syntaxhighlight lang=bash>
			for i in {00..59}
			do
			echo ${i}
			done

			for i in $(seq ${START} ${END})
			do
			echo $i
			done
			</syntaxhighlight>

2019-03-15T07:53:13Z

← Older revision		Revision as of 07:53, 15 March 2019
Line 1:		Line 1:
	[[Category:Bash]]		[[Category:Bash]]
	~~Bash is a *nix shell. Much more is still in [https://unix.antiperfect.org the antiperfect unix site].~~

	~~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>~~

	=Arithmetics=		=Arithmetics=

2019-03-15T07:40:20Z

← Older revision		Revision as of 07:40, 15 March 2019
Line 1:		Line 1:
	[[Category:Bash]]		[[Category:Bash]]
	Bash is a *nix shell. Much more is still in [https://unix.antiperfect.org the antiperfect unix site].		Bash is a *nix shell. Much more is still in [https://unix.antiperfect.org the antiperfect unix site].

	~~;echo -n <string>~~
	~~:Print <string> without newline~~

	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.		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.

2019-03-15T07:38:47Z

Hdridder moved page Bash to Bash:Variables without leaving a redirect: Specific name as more bassh pages appear

← Older revision		Revision as of 07:38, 15 March 2019
(No difference)