Bash script containing binary executable

Question

Is it possible to write a bash script, which would contain a binary executable program inside?

I mean a script, which would contain a dump of an executable in a textual form, which will be dumped back to an executable by this script when it is executed?

I would love to know a solution, which will work out of the box without a need of installing additional packages. Is it possible?

Thanks!

Answer 1

Don't reinvent the wheel like several other answers are suggesting, just use the venerable shar command which is precisely doing this by design.

Assuming the file you want to embed in your script is binaryfile, simply run

$ shar binaryfile > binaryfile.shar

and you are set. You have a shell script named binaryfile.shar which when executed will extract binaryfile.

Answer 2

i never done something like this before ;) this will compile some c source, create a b.bash script containing the binary (and the original script for simple development)

(a.bash)

#!/bin/bash

if [ "$0" == "b.bash" ];then
  tail -n +$[ `grep -n '^BINARY' $0|cut -d ':' -f 1` + 1 ] $0 | base64 -d > a2.out
  chmod +x a2.out
  ./a2.out
  echo $?
  exit
fi

cat "$0" > b.bash
echo "BINARY" >> b.bash
cat > a.c << EOF
int     main(){
        return 12;
}
EOF
gcc a.c 
base64 a.out >> b.bash

invoke with (a.bash generates b.bash):

bash a.bash ;bash b.bash

i don't know how to evade writing out the binary into a temporary file before execution...