Tech-Recipes - Latest Comments in Bourne/bash shell scripts: string comparison | Bourne shell scripting | Tech-Recipes

Re: Bourne/bash shell scripts: string comparison | Bourne shell scripting | Tech-Recipes

Florin — Thu, 16 Apr 2009 08:35:45 -0000

This is the method i curently to test if a string is empty:

if [ "X${VAR}" = "X" ]; then
echo "Empty string"
fi

Testing for equality follows the same logic but without X.

Re: Bourne/bash shell scripts: string comparison | Bourne shell scripting | Tech-Recipes

asd — Thu, 02 Apr 2009 04:58:39 -0000

These examples don't work.

Re: Bourne/bash shell scripts: string comparison | Bourne shell scripting | Tech-Recipes

bhargav — Fri, 27 Mar 2009 13:15:41 -0000

if [ "$var" = "value" ]
then
echo not the same
fi

Re: Bourne/bash shell scripts: string comparison | Bourne shell scripting | Tech-Recipes

Anonymous — Tue, 21 Oct 2008 23:38:39 -0000

i believe the $var needs to be in quotes, like so:

if [ -z "$var" ];then
echo null
fi

Best Regards,
Kibokina

Re: Bourne/bash shell scripts: string comparison | Bourne shell scripting | Tech-Recipes

BhupinderSingh — Fri, 10 Jun 2005 00:43:20 -0000

this can also be used to compare 2 strings

s1 = "as"
s2 = "bs"

if test $s1 == $s2
then
echo s1 and s2 are equal
fi

Re: Bourne/bash shell scripts: string comparison | Bourne shell scripting | Tech-Recipes

guest — Thu, 04 Mar 2004 19:35:13 -0000

the following syntax is wrong

if [ $var == "" ] ......

because if the variable $var is empty the test is
if [ == "" ] and gives an error

you are obliged to quote the var :
if [ "$var" == "" ] ...

Sergio

Re: Bourne/bash shell scripts: string comparison | Bourne shell scripting | Tech-Recipes

Anonymous — Sun, 01 Feb 2004 10:47:19 -0000

Wouldn't the following be better?

if [ -z $var ];then
echo null
fi