What is wrong with my Linux installation if my script won't run with the following error messages

Question

Trying to run some .sh scripts in a very cut down Ubuntu installation, but I'm getting messages of the following style:

./my_script: 61: [[: not found
./my_script: 61: ==: not found
./my_script: 61: ==: not found
./my_script: 61: ==: not found
./my_script: 67: [[: not found
./my_script: 73: [[: not found

There is obviously something not quite right :)

The script starts with:

#!/bin/sh

Edit

It runs ok if I start it like this:

bash ./my_script

Edit 2

Sorry, that was a stupid question without some more explanation :) This script works fine, unchanged, on some RHEL machines - what do I need to change on the Ubuntu box to get the script to work, without modifying the script?

Answer 1

Try changing bin/sh to bin/bash

to address the last edit to the question...you need to make /bin/sh a symlink to /bin/bash
ubuntu customized their default shell a bit...this may have other side effects though, be careful

-rwxr-xr-x 1 root root 801808 2010-08-10 15:58 bash
-rwxr-xr-x 1 root root 87984 2010-06-24 16:01 dash
lrwxrwxrwx 1 root root 4 2010-10-16 21:58 rbash -> bash
lrwxrwxrwx 1 root root 4 2010-10-16 21:58 sh -> dash
lrwxrwxrwx 1 root root 4 2010-10-16 21:58 sh.distrib -> bash
lrwxrwxrwx 1 root root 7 2010-10-16 21:58 static-sh -> busybox

it's just a symlink anyway, if it breaks something you need change it back.

in answer to grawity "There's no other at least remotely sane way."

according to: http://ubuntuforums.org/archive/index.php/t-499045.html
some users have been doing this since 2007 and have experienced little negative side effect...i might not call that insanity

Answer 2

The difference seems quite obvious:

• When you type bash, you execute bash.
• When you type ./myscript, it executes sh (the #! line).

If the script uses bash-specific features, it should start with #!/bin/bash (or maybe #!/usr/bin/env bash).