How can I configure bash to handle CRLF shell scripts?

Question

I want to execute bash scripts that happen to use Windows/CRLF line endings.

I know of the tofrodos package, and how to fromdos files, but if possible, I'd like to run them without any modification.

Is there an environment variable that will force bash to handle CRLF?

Answer 1

Perhaps like this?

dos2unix < script.sh|bash -s

EDIT: As pointed out in the comments this is the better option, since it allows the script to read from stdin by running dos2unix and not bash in a subshell:

bash <(dos2unix < script.sh)

Answer 2

Here's a transparent workaround for you:

cat > $'/bin/bash\r' << "EOF"
#!/bin/bash
script=$1
shift
exec bash <(tr -d '\r' < "$script") "$@"
EOF

This gets rid of the problem once and for all by allowing you to execute all your system's Windows CRLF scripts as if they used UNIX eol (with ./yourscript), rather than having to specify it for each particular invocation. (beware though: bash yourscript or source yourscript will still fail).

It works because DOS style files, from a UNIX point of view, specify the interpretter as "/bin/bash^M". We override that file to strip the carriage returns from the script and run actual bash on the result.

You can do the same for different interpretters like /bin/sh if you want.