initial version

README

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+*shasumscript* is a tool to generate a self-checksum-script.
+
+
+Usage
+
+	shasumscript script.sh
+
+License
+
+MIT
+
+From an idea of LSC https://github.com/dealfonso/lsc
+
+

shasumscript

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+#!/bin/sh
+# Script to add a SHA256 checksum to a file
+# Usage: shasumscript <file>
+# Output: <file>_sha256
+# Requires: shasum
+# License: MIT
+# Author: Patrick Cao Huu Thien
+
+set -e
+
+error() { printf "Error: \e[31m%s\e[0m\n" "$*" >&2; }
+err() { error "$*"; exit 1; }
+usage() { echo "Usage: $(basename "$0") [-V | -h] <file>";echo "  -V: Show version"; echo "  -h: Show this help"; }
+err_usage() { error "$*"; usage; exit 1; }
+step () { err="$?"; c=32; t=OK; test "$err" = 0 || { c=31; t=FAILED; }; printf "* %s \e[%dm%s\e[0m\n" "$*" "$c" "$t"; }
+
+VERSION="0.0.1"
+if test "$1" = '-V'; then echo "shasumscript v$VERSION"; exit; fi
+if test "$1" = '-h'; then usage; exit; fi
+
+file="$1"
+test -n "$file" || err_usage "Missing file argument"
+test -e "$file" || err "File not found: $file"
+
+sha="$(shasum -a 256 "$file" | cut -d' ' -f1)" || err "Failed to calculate SHA256 checksum"
+step "Checksum"
+
+newfile="${file}_sha256"
+
+cat <<EOT > "$newfile"
+#!/bin/sh
+# script generated by shasumscript at $(date)
+#
+# This script self-checkssum it's content and exit on error
+# The real script can be found after the separator:
+# $sha
+#
+# License: MIT
+# Author: Patrick Cao Huu Thien
+
+tmpexe="\$(mktemp)"
+trap 'rm -f "\$tmpexe"' EXIT
+
+cat "\$0" | sed -n '/^${sha}/,\$p' | tail -n +2 > "\$tmpexe"
+test "\$(shasum -a 256 "\$tmpexe" | cut -d' ' -f1)" = "$sha" || {
+	echo "Checksum mismatch!" >&2
+	exit 1
+}
+
+printf "Checksum OK"; sleep 1; printf "\r                         \r"
+
+sh "\$tmpexe" "\$@"
+
+exit
+$sha
+EOT
+step "pre-script"
+
+cat "$file" >> "$newfile"
+step "post-script"
+
+chmod +x "$newfile"
+step "make it executable"
+echo
+cat <<EOT
+File created: $newfile
+
+You can distribute it.
+
+To run it:
+	./$newfile
+EOT
+
+