mjhjmtu

Here's a simple line from a bigger piece of code which is what I am confused about.

if [ $some_line == "text" ]
then

Then I went on to use the same code for another program that I was working on but the code didn't work UNLESS I changed "==" to "=". I've gone through a few threads here that suggests both of them act the same way so it doesn't matter if you use single or double equals.

if [ $some_line = "text" ]
then

So the first piece of code works on server1 but doesn't on server2 UNLESS I change it to "single equals". Both the servers have exactly the same environment.

Can anyone explain?
Thanks!

EDIT - I am running the script as "bash myscript.sh" everytime.

== and = are equivalent inside [ ] tests in bash.

== doesn't work in sh, only =

Are you running both scripts with the same shell?

Example:

$ cat test1
#!/bin/bash
if [ "a" == "a" ];then echo match;fi
$ ./test1
match
$ cat test2
#!/bin/bash
if [ "a" = "a" ];then echo match;fi
$ ./test2
match
$ cat test3
#!/bin/sh
if [ "a" = "a" ];then echo match;fi
$ ./test3
match
$ cat test4
#!/bin/sh
if [ "a" == "a" ];then echo match;fi
$ ./test4
./test4: 2 [: a: unexpected operator