Bash: How to extract an executable from within?

Daniel B. Thurman dant at
Tue Sep 15 00:48:37 UTC 2009

I noticed that some (older?) shell-scripts have
self-extracting executables built in and extracting
was done done by using a tail +N $0 where N is the
line number where the executable line is located to
the end of the file. Unfortunately, Fedora's tail program
does not support the +N option.

I am looking for an alternative.

I tried to wrap the executable with a function such as:


function unWrapExe() {
cat <<'EOF'

# Do pre-shell stuff

unWrapExe > $outname

# Do post-shell stuff

The problem as I see it, is somehow cat blows
up when certain characters appear in the input
stream and the output executable file becomes
corrupted cannot be executed.  I have tried
echo and I cannot think of another program to

So, how does one go about fixing these sort of
problems nowadays?


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