Shebang line limit in bash and linux kernel

If you don't want to recompile your kernel to get longer shebang lines, you could write a wrapper:

#!/bin/bash

if [[ $# -eq 0 ]]; then
    echo "usage: ${0##*/} script [args ...]"
    exit
fi

# we're going to expand a variable *unquoted* to use word splitting, but
# we don't want to have path expansion effects, so turn that off
set -f

shebang=$(head -1 "$1")
if [[ $shebang == '#!'* ]]; then
    interp=( ${shebang#\#!} )        # use an array in case a argument is there too
else
    interp=( /bin/sh )
fi

# now run it
exec "${interp[@]}" "$@"

and then run the script like: wrapper.sh script.sh

Limited to 127 chars on 99.9% of systems due to kernel compile time buffer limit.

It's limited in the kernel by BINPRM_BUF_SIZE, set in include/linux/binfmts.h.