Comparing strings for equality in ksh

bash unix shell ksh

Vijay · Nov 2, 2009 · Viewed 61k times · Source

i am testing with the shell script below:

#!/bin/ksh -x


instance=`echo $1 | cut -d= -f2`
if [ $instance == "ALL" ]
then
echo "strings matched \n"
fi

It's giving this error in the if condition:

: ==: unknown test operator

is == really not the correct syntax to use? I am running on the command line as below

test_lsn_2 INSTANCE=ALL

Could anybody please suggest a solution. Thanks.

Answer

To compare strings you need a single =, not a double. And you should put it in double quotes in case the string is empty:

if [ "$instance" = "ALL" ]
then
    echo "strings matched \n"
fi