linux - [Solved-5 Solutions] How to compare two string variables in an 'if' statement in Bash - ubuntu - red hat - debian - linux server - linux pc

How to compare two string variables in an 'if' statement in Bash ?

For string comparison, use:

if [ "$s1" == "$s2" ]

For the a contains b, use:

if [[ $s1 == *"$s2"* ]]

Ensure to add spaces between the symbols:

if [ "$s1" == "$s2" ]

You need spaces:

if [ "$s1" == "$s2" ]

You should be careful to leave a space between the sign of '[' and double quotes where the variable contains this:

if [ "$s1" == "$s2" ]; then
#   ^     ^  ^     ^
   echo match
fi

The ^s show the blank spaces you need to leave.

if [ "$a" = "$b" ]

Notice the white space between the openning/closing brackets and the variables and also the white spaces wrapping the '=' sign.

Also, be careful of your script header. It's not the same thing whether you use

#!/bin/bash

or

#!/bin/sh

#!/bin/bash

s1="welcome to wikitechy"
s2="welcome to wikitechy"

if [ $s1 = $s2 ]
then
  echo match
fi

Without the double quotes and with only one equals.