I'm working on an "edgemax feature-wizard" which is kind of a plugin system. There are only three files allowed in a plugin tarball: a bash script as backend, a HTML file as frontend and a validation.json file for input validation from frontend, so please don't ask why I don't just put the deb packages into the tarball -- they get ignored.

I want to ship deb packages with that "wizard" so I have to base64 encode the files and put it into the bash script to be extracted when the script is run. Now, I know how to do all this, but I'm doing it manually by copy-pasting the base64 part into the bash file and then cut-paste into right position, which is unhandy when updating those packages to recent version.

Would there be a possibility to encode the deb files in base64 and write it to line 65 of the bash script?

I've read this article and I tried

sed -i "65i\\$(base64 package.deb)" wizard-run

but that complains with:

bash: /bin/sed: Argument list too long

Here's my code; the base64-part has to go within the double-quotes from the echo statement:

if [ $arch == 'mips' ]; then
    # base64: olsrd_0.9.0.3-1_mips.deb
    echo "
    " | base64 -d > $cfgusrdir/olsrd_0.9.0.3-1_mips.deb
    # base64: olsrd-plugins_0.9.0.3-1_mips.deb
    echo "
    " | base64 -d > $cfgusrdir/olsrd-plugins_0.9.0.3-1_mips.deb
  • 1
    use a here document
    – mikeserv
    Oct 24, 2016 at 19:41
  • 1
    +1 to the heredoc - however, at least if you have GNU sed, you could probably do base64 package.deb | sed -i '65r /dev/stdin' wizard-run Oct 24, 2016 at 20:27
  • great, that did it, thanks! is there a way to also remove newline at the end? Oct 24, 2016 at 21:26

1 Answer 1


Using sed and I/O redirection:

  sed -n '1,64p' wizard-run;
  base64 package.deb;
  sed -n '66,$p' wizard-run;
} > wizard-run.tmp && mv wizard-run.tmp wizard-run
  • good idea, but i dont understand why, that fills the wizard-run with the base64 part running in loop until i press ctrl+c .. Oct 24, 2016 at 21:01
  • 1
    @vchrizz Oops, writing to the file you are writing to is a bad idea (see github.com/koalaman/shellcheck/wiki/SC2094). My bad, will fix it.
    – phk
    Oct 24, 2016 at 21:32
  • ok that worked now, how do i remove newline from beginning and end? Oct 24, 2016 at 21:52
  • @vchrizz Beginning and end of what? wizard-run?
    – phk
    Oct 24, 2016 at 22:21
  • 1
    @vchrizz Try the -i parameter of base64.
    – phk
    Oct 24, 2016 at 22:30

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