mergetags -- A tool to update entries for a single file in a CTags tag file

mergetags

#!/bin/sh
# 
# FIXME: better error checking.  As many commands are piped, their return code
#        is not properly checked.

export LANG=C

set -e

### argument parsing

sort=true
tagfile=tags
ctags=ctags

usage() {
    cat <<EOF
USAGE: $0 [-h] [-c CTAGS] [-o TAGFILE] [-s|-S] [-v|-q] FILE

 -c CTAGS       Use CTAGS as the CTags executable instead of "$ctags"
 -h             Show this help and exit
 -o TAGFILE     Update TAGFILE instead of "$tagfile"
 -q             Be quiet
 -s             Sort output
 -S             Do not sort output
 -v             Be verbose
 
EOF
    exit "$1"
}

while getopts 'c:ho:sSvq' o; do
    case "$o" in
        c)  ctags="$OPTARG";;
        h)  usage 0;;
        o)  tagfile="$OPTARG";;
        q)  set +x;;
        s)  sort=true;;
        S)  sort=false;;
        v)  set -x;;
        *)  usage 1 >&2;;
    esac
done
shift $((OPTIND - 1))

[ $# -eq 1 ] || usage 1 >&2

input="$1"


### main logic

tmp=$(mktemp -p "$(dirname "$tagfile")" "$(basename "$tagfile").XXXXXX")

(
    # remove the existing tags for the file
    grep -vF "	$input	" "$tagfile"
    # and add new at the end
    "$ctags" -o- "$input"
) | (
    if "$sort"; then
        # extract the pseudo-tags
        sed -n '/^!_TAG_/!q;p' "$tagfile"
        # and sort the rest
        sed '/^!_TAG_/d' | sort -u
    else
        cat
    fi
) > "$tmp"

mv -f "$tmp" "$tagfile"