Shell Programming and Scripting

You are right about the ! oversight. But, even if it were there, it wouldn't be used. The shebang, #!/bin/bash, is only relevant when the script file itself is executed (the execve system call provides this service). In this case, sudo is explicitly exec-ing sh.

I am not an Ubuntu user, but, I seem to recall reading that, due to poor performance, sh was changed from bash to dash to speed up the boot process. I think it may also be the default shell for the root user (although bash is still used by non-privileged users).

Regards,
Alister

Well spotted @244an and @alister.

@kitay
1) First, please edit the script to fill in the missing exclamation mark on the shebang line:

Code:

#!/bin/bash
echo "Test script"
read cake
if [ "$cake" == "1" ]
then
    echo "cake it is"
fi

2) Please try running the script as

Code:

./scriptname

3) If for some reason you have to use sudo sh test.sh then it would appear that whatever Shell corresponds to sh does not support the bash double equals sign, then try agan with a single equals sign because as @alister rightly advises, the shebang line would be ignored:

Code:

#!/bin/bash
echo "Test script"
read cake
if [ "$cake" = "1" ]
then
    echo "cake it is"
fi