fix-c-header-comment.sh

#!/bin/bash

# Fix source file header by removing current header and inserting standard copyright notice
# Works for all C-based files, uses // comment style, current year and specified company name
# Doesn't work for empty files

# Temp directory
TMP_DIR=$(mktemp -dt "XXXXXXXX")

# Log
log () {
	[[ -n "$VERBOSE" ]] && echo -e "$@"
}

# Usage
usage () {
	echo "usage: $(basename $0) [-v|--verbose] [-i|--inplace] [-c|--company COMPANY] FILE_PATH [-o|--output OUTPUT_PATH]" 1>&2
	echo "usage: $(basename $0) -h|--help" 1>&2
	echo "Options:" 1>&2
	echo -e "\tFILE_PATH\t\t\tPath to the source file." 1>&2
	echo -e "\t-c, --company COMPANY\t\t\tCompany name to put in copyright notice." 1>&2
	echo -e "\t-i, --inplace\t\t\tInplace edit (modify source file). By default output is written to stdout." 1>&2
	echo -e "\t-o, --output OUTPUT_PATH\tSave output to given file path." 1>&2
	echo -e "\t-v, --verbose\t\t\tVerbose output." 1>&2
	echo -e "\t-h, --help\t\t\tDisplay this message." 1>&2

	exit 2
}

# Parse args
while [ "$1" != "" ]; do
	case $1 in
		-i | --inplace )
			INPLACE="YES"
			;;
		-c | --company )
			shift
			COMPANY="$1"
			;;
		-o | --output )
			shift
			OUTPUT_PATH="$1"
			;;
	    	-v | --verbose )
			VERBOSE="YES"
			;;
		-h | --help )
			usage
			;;
		* )
			# Only one expected
			[[ -n "${FILE_PATH}" ]] && echo "Only one source file path expected!" && usage
			FILE_PATH="$1"
			;;
	esac

	# next arg
	shift
done

# Can't have inplace and output path
[[ -n "${INPLACE}" && -n "${OUTPUT_PATH}" ]] && echo "Can't specify inplace and output path options at the same time!" && usage

# Temp path
FILE_NAME="$(basename ${FILE_PATH})"
TMP_PATH="${TMP_DIR}/${FILE_NAME}"
cp -f "${FILE_PATH}" "${TMP_PATH}"

# First strip leading blank lines
sed -i . '/./,$!d' "${TMP_PATH}"

# Do nothing if file start with block comment (/*)
STARTS_WITH_BLOCK="$(head -n1 ${TMP_PATH} | grep '^/\*.*' )"
[[ -n "${STARTS_WITH_BLOCK}" ]] && echo "File starts with block comment. Ignoring." && exit 0

# Remove current header
# Not an optimal way - first count // lines with awk, then removed that number of lines with sed
N=$(cat "${TMP_PATH}" | awk '{ if(/^\/\//) print; else exit; }' | wc -l | xargs)
# Do nothing if count is 0
[[ ${N} -gt 0 ]] && sed -i . "1,${N}d" "${TMP_PATH}"

# And cleanup leading blank lines again
sed -i . '/./,$!d' "${TMP_PATH}"

# Insert new header using current year
HEADER="//\\
//  Copyright (c) $(date +'%Y') ${COMPANY}. All rights reserved.\\
//\\
\\
"

sed -i . "1s|^|${HEADER}|g" "${TMP_PATH}"

# Produce output
if [[ -n "${INPLACE}" ]]; then
	mv -f "${TMP_PATH}" "${FILE_PATH}"
elif [[ -n "${OUTPUT_PATH}" ]]; then
	mv -f "${TMP_PATH}" "${OUTPUT_PATH}"
else
	cat "${TMP_PATH}"
fi