A bash script that compiles Google Chrome extension folders into .crx files

crx-build.sh

#!/bin/bash -e
#
# Purpose: Pack a Chromium extension directory into crx format

if test $# -ne 2; then
  echo "Usage: crxmake.sh <extension dir> <pem path>"
  exit 1
fi

dir=$1
key=$2
name=$(basename "$dir")
crx="$name.crx"
pub="$name.pub"
sig="$name.sig"
zip="$name.zip"
trap 'rm -f "$pub" "$sig" "$zip"' EXIT

# zip up the crx dir
cwd=$(pwd -P)
(cd "$dir" && zip -qr -9 -X "$cwd/$zip" .)

# signature
openssl sha1 -sha1 -binary -sign "$key" < "$zip" > "$sig"

# public key
openssl rsa -pubout -outform DER < "$key" > "$pub" 2>/dev/null

byte_swap () {
  # Take "abcdefgh" and return it as "ghefcdab"
  echo "${1:6:2}${1:4:2}${1:2:2}${1:0:2}"
}

crmagic_hex="4372 3234" # Cr24
version_hex="0200 0000" # 2
pub_len_hex=$(byte_swap $(printf '%08x\n' $(ls -l "$pub" | awk '{print $5}')))
sig_len_hex=$(byte_swap $(printf '%08x\n' $(ls -l "$sig" | awk '{print $5}')))
(
  echo "$crmagic_hex $version_hex $pub_len_hex $sig_len_hex" | xxd -r -p
  cat "$pub" "$sig" "$zip"
) > "$crx"
echo "Wrote $crx"

According to http://mywiki.wooledge.org/ParsingLs and some other sites, it's a bad idea to parse "ls" output in Bash scripts, in part because file names on many systems are allowed to have newlines and other strange characters in them. "stat -c%s" works OK for me in Ubuntu, but the above-referenced page says that "stat" is not very portable, and suggests using "wc" instead. So instead of:

pub_len_hex=$(byte_swap $(printf '%08x\n' $(ls -l "$pub" | awk '{print $5}')))
sig_len_hex=$(byte_swap $(printf '%08x\n' $(ls -l "$sig" | awk '{print $5}')))

...the code might be more stable if it was something like:

pub_len_hex=$(byte_swap $(awk '{printf "%08x\n",$1}' <(wc -c "$pub")))
sig_len_hex=$(byte_swap $(awk '{printf "%08x\n",$1}' <(wc -c "$sig")))

Caveat: I have NOT tested the above example code, so apply grains of salt accordingly.

This code worked for me. Thank you!!!

This doesn't work anymore.
Apart than having to change the way of getting the file size as @willdye said, Chrome says Package is invalid: 'CRX_HEADER_INVALID' when trying to install it, I don't know why.
Has anyone found a workaround for this?

is PEM file necessary?

This doesn't work anymore.
Apart than having to change the way of getting the file size as @willdye said, Chrome says Package is invalid: 'CRX_HEADER_INVALID' when trying to install it, I don't know why.
Has anyone found a workaround for this?

Even I am getting the same issue.