cutlink - convert hard-linked file to just a copied file.

cutlink

#!/bin/sh
#
# cutlink - Convert hardlink-ed file to just a copy.
#
#   Basically, the command does the following, with many checks.
#
#       $ cp $file $file.tmp
#       $ rm -f $file
#       $ mv $file.tmp $file
#

progname="${0##*/}"

DIE () {
    echo "ERROR: $@" >&2
    exit 1
}

HELP () {
    echo "$progname: convert hardlink-ed file to just a copy."
    echo "Usage: $progname HARDLINKED_FILE"
    echo "Usage: $progname -s SYMLINKED_FILE_OR_DIR"
    echo "OPTIONS:"
    echo "  -s,--symlink  Cutlink for symlink instead of hardlink (allow directory)"
}

cut_hardlink () {
    if [ -d "$1" ]; then
        DIE "$1 is a directory (use --symlink for symlink-ed directory)"
    fi

    if [ ! -e "$1" ]; then
        DIE "$1 doen't exist"
    fi

    if [ ! -r "$1" ]; then
        DIE "$1 is not readable"
    fi

    link_count=`stat -c %h "$1"`
    if [  $link_count -le 1 ]; then
        DIE "$1 is not hard-linked (link count is $link_count)"
    fi

    echo -n "Old: ";ls -i $1

    tmp_filename="$1.tmp.$$"
    trap 'echo "Aborintg ..."; rm -f "$tmp_filename"; exit 1' INT
    if cp "$1" "$tmp_filename"
    then
        trap "echo Cannot abort" INT
        rm -f "$1"
        mv "$tmp_filename" "$1"
        chmod +w "$1"
    else
        rm -f "$tmp_filename"
        DIE "Copy to $tmp_filename failed"
    fi
    trap - INT

    echo -n "New: "; ls -i $1
}


cut_symlink () {
    if [ ! -L "$1" ]; then
        DIE "$1 is not symlink"
    fi

    echo -n "Old: ";ls -ld $1

    tmp_filename="$1.tmp.$$"
    trap 'echo "Aborintg ..."; rm -rf "$tmp_filename"; exit 1' INT

    if {
        if [ -d "$1" ]; then
            cp -a "$1"/ "$tmp_filename"
        else
            cp "$1" "$tmp_filename"
        fi
    }
    then
        trap "echo Cannot abort" INT
        rm -f "$1"
        mv "$tmp_filename" "$1"
        chmod +w "$1"
    else
        rm -f "$tmp_filename"
        DIE "Copy to $tmp_filename failed"
    fi
    trap - INT
    echo -n "New: ";ls -ld $1
}


case $1 in
    -h|--help)
        HELP
        exit 0
        ;;
    -s|--symlink)
        opt_symlink=yes
        shift
        ;;
    -*)
        DIE "Unknown option: $1"
        ;;
esac


if [ -z "$1" ]; then
    DIE "No file specified. See '$progname --help' for help."
fi

if [ "$opt_symlink" == "yes" ]; then
    for file in "$@"
    do
        cut_symlink "$file"
    done
else
    for file in "$@"
    do
        cut_hardlink "$file"
    done
fi