Quick bash script to create self-extracting .sh files /w Base64 encoded contents (e.g. binary, zip, etc)

create_self_extracting_script.sh

#!/bin/bash
#
# create_self_extracting_script.sh <INPUT_FILE> [<OUTPUT_SCRIPT>]
#
# Creates a self-extracting shell script containing INPUT_FILE as Base64-encoded
# bytes. When executed, the script writes INPUT_FILE and restores its permissions.
#
# (c) Jeff Ward, 2017
# MIT License

FILENAME=$1
SCRIPT=${2:-extract.sh}

if [[ $# -eq 0 ]] ; then
    echo "Usage: $0 INPUT_FILE [OUTPUT_SCRIPT]"
    exit 0
fi

if [ ! -f "$FILENAME" ]; then
    echo "File not found: $FILENAME"
    exit 1
fi

echo "Writing $SCRIPT"

# Capture current permissions
PERMS="644"
if [[ "$OSTYPE" == "linux-gnu" ]]; then
    PERMS=`stat -c "%a" "$FILENAME"`
elif [[ "$OSTYPE" == "darwin"* ]]; then
    PERMS=`stat -f "%A" "$FILENAME"`
fi

cat > "$SCRIPT" << EOF

FILENAME="$FILENAME"

# Extract the .zip file
LINES=\`awk '/^__BASE64_ARCHIVE__/ {print NR + 1; exit 0; }' "\$0"\`
tail -n+\$LINES "\$0" | base64 --decode > "\$FILENAME" || { echo "Failed to write \$FILENAME" ; exit 1; }

# Restore permissions
chmod $PERMS "\$FILENAME"

echo "Extracted ./\$FILENAME"
exit 0

__BASE64_ARCHIVE__
EOF

base64 "$FILENAME" >> "$SCRIPT"
chmod a+x "$SCRIPT"