#!/bin/ksh
# @(#) shorten.ksh 1.1 92/10/24
# 92/10/24 john h. dubois iii (john@armory.com)
# 92/12/05 changed -<maxlength> option to -m<maxlength>

Usage="Usage: ${0##*/} [-ht] [-m<maxlength>|-[aA] <names-across>] filename ..."
length=23
cmd=mv

while getopts :hta:A:m: opt; do
    case $opt in
    h) echo \
"${0##*/}: shorten filenames.
${0##*/} truncates filenames to a given maximum length.  The default is 23.
${0##*/} will not overwrite files when renaming.
$Usage
Options:
-m<maxlength>: truncate filenames to <maxlength> characters.
-a <names-across>: truncate filenames to the maximum length that will
   allow lf to print <names-across> filenames across an 80-column display.
-A <names-across>: same as -a except that if the environment variable COLUMNS
   is set it is used for the display width.
-t: test.  ${0##*/} reports what it would do but does not rename any files.
-h: print this help."
       exit 0;;
    # lf uses this formula which puts 3 unneeded spaces at the end of the line.
    a) length="80/($OPTARG+3)";;
    A) [ -z "$COLUMNS" ] && COLUMNS=80
       length="$COLUMNS/($OPTARG+3)";;
    m) length=$OPTARG;;
    t) cmd="echo mv";;
    +?) echo "$0: options should not be preceded by a '+'."; exit 1;;
    ?) echo "$0: $OPTARG: bad option.  Use -h for help."; exit 1;;
    esac
done
 
# remove args that were options
let OPTIND=OPTIND-1
shift $OPTIND

# If a non-number was given for a numeric option,
# this will make length empty.
typeset -i length

if [ $# -lt 1 -o length -eq 0 ]; then
    echo "$Usage"
    exit 1
fi

typeset -L$length fixwid

for file; do
    fixwid=$file
    newname=${fixwid%%*( )}	# get rid of space padding done by typeset -L
    [ "$file" = "$newname" ] && continue
    if [[ -a "$newname" ]]; then
	print -u2 "$newname exists.  $file not renamed."
	continue
    fi
    $cmd "$file" "$newname"
done