Making bash run DOS/Windows CRLF EOL scripts
If you for any reason use a Windows editor to write scripts, it can be annoying to remember to convert them and bash fails in mysterious ways when you don’t. Let’s just get rid of that problem once and for all:
cat > $'/bin/bash\r' << "EOF" #!/usr/bin/env bash script=$1 shift exec bash <(tr -d '\r' < "$script") "$@" EOF
This allows you to execute scripts with DOS/Windows \r\n line endings with
./yourscript (but it will fail if the script specifies parameters on the shebang, or if you run it with
bash yourscript). It works because from a UNIX point of view, DOS/Windows files specify the interpretter as "bash^M", and we override that to clean the script and run bash on the result.
Of course, you can also replace the helpful exec bash part with
echo "Run dos2unix on your file!" >&2 if you'd rather give your users a helpful reminder rather than compatibility or a crazy error.