path: root/functions

#!/bin/sh

# Comments on coding style:
#  * shift mandatory function arguments: Provokes error if missing
#  * quote variables: We want to support oddities like spaces in paths

function preserveolderfile() {
    ## DESC: Preserve copy of file, unless one exists already
    # File to tweak
    file="$1"; shift
    # Extension used for new backup
    newext="$1"
    # Space-delimited list of possible extensions, default last
    extensions="orig old"
    for ext in $extensions; do
        backupfile="$file.$ext"
        [ "$ext" = "$newext" ] && newext_valid="yes"
        if [ -f "$backupfile" ]; then
            [ -n "$DEBUG" ] && echo "DEBUG: Backup file \"$backupfile\" not found - continuing." >&2
            continue
        elif [ -e "$backupfile" ]; then
            echo "ERROR: Backup file \"$backupfile\" is not a regular file." >&2
            return 1
        else
            [ -n "$DEBUG" ] && echo "DEBUG: Backup file \"$backupfile\" found - exit silently." >&2
            return 0
        fi
    done
    if [ -n "$newext" ];then
        if [ "$newext_valid" = "yes" ]; then
            backupfile="$file.$newext"
        else
            echo "WARNING: Backup extension \"$newext\" is invalid - using default instead" >&2
        fi
    fi
    if [ -f "$file" ]; then
        cp -p "file" "$backupfile"
    elif [ -e "$file" ]; then
        echo "ERROR: Backup of file \"$file\" failed - not a regular file." >&2
        return 1
    else
        touch "$backupfile"
    fi
    return 0
}

function enableoraddlines() {
    ## DESC: Add lines to file, or replace if similar exist already
    # File to tweak
    file="$1"; shift
    # Word number in line to search for and replace if found
    wordno="$1"; shift
    [ -e "$file" ] || touch "$file"
    for line; do
        [ -z "$line" ] && continue
        firstword=$(echo "$line" | awk "{print \$$wordno}")
        # FIXME: Why doesn't it work to print ARGVOUT in END block?
        linemissing=$(perl -i -pe "END { print \"$line\\n\" unless \$seen } s¡^[#;\s]*($firstword)\s.*¡$line\\n¡ and \$seen++" "$file")
#"This stray quote is only to please buggy mc (cooledit) code hiliting
        [ -n "$linemissing" ] && echo $linemissing >> "$file"
    done
    # FIXME: Figure out what exits non-zero above
    return 0
}

function preserveandaddlines() {
    ## DESC: Backup older file and add lines to it
    # File to tweak
    file="$1"; shift
    # Extension of backup file
    ext="$1"; shift
    # Word number in line to search for and replace if found
    wordno="$1"; shift
    preserveolderfile "$file" "$ext"
#   enableoraddlines "$file" "$wordno" $@
    # FIXME: Somehow avoid expansion, to avoid having to duplicate the whole enableoraddlines()
    [ -e "$file" ] || touch "$file"
    for line; do
        [ -z "$line" ] && continue
        firstword=$(echo "$line" | awk "{print \$$wordno}")
        # FIXME: Why doesn't it work to print ARGVOUT in END block?
        linemissing=$(perl -i -pe "END { print \"$line\\n\" unless \$seen } s¡^[#;\s]*($firstword)\s.*¡$line\\n¡ and \$seen++" "$file")
#"This stray quote is only to please buggy mc (cooledit) code hiliting
        [ -n "$linemissing" ] && echo $linemissing >> "$file"
    done
    # FIXME: Figure out what exits non-zero above
    return 0
}

function perlrelines() {
    ## DESC: Apply perl regex to lines of a single file
    # File to tweak
    file=$1; shift
    backupfile="`savebackupfile "$file"`"
    for regexp; do
        perl -pi -e "$regexp" "$file"
    done
    cleanbackupfile "$file" "$backupfile"

    # FIXME: Figure out what exits non-zero above
    return 0
}

function mkgrubdevmap() {
    ## DESC: Spit out GRUB config used for /boot/grub/devices.map
    device="$1"; shift
    cat <<EOF
(fd0) /dev/fd0
(hd0) $device
EOF
}

function addaddons() {
    set -x
    context="$1"; shift
    addon_context="$1"; shift
    for addon in $@; do
        context_here="$(eval echo \$\{${addon_context}_$addon\})"
        if [ -n "$context_here" ]; then
            eval ${context}=\"\$${context} \$context_here\"
        else
            echo "Warning: Variable \"${addon_context}_${addon}\" empty or undefined!"
        fi
done
}