nmv

UNIX下SH的实现源码

#! /bin/bash
#
# original from:
# @(#) ncp.ksh,nmv.ksh 1.1 94/07/23
# 92/01/18 john h. dubois iii ([e-mail])
# 92/01/31 added check for no args left after shifts
# 92/02/17 added help
# 92/02/25 remove path component from filename before tacking it onto dest.
# 92/03/15 exec mv or cp
# 93/07/13 Added -i
# 93/09/29 Made abort if file exists optional.
# 93/11/19 Exit before invoking mv if no files to move
# 94/01/03 Added o option
# 94/04/13 Added x option.
#          Fixed appending of source filename, broken by earlier change.
# 94/07/23 Append only the filename part of the source path.
#
# conversion to bash v2 syntax done by Chet Ramey

false()
{
	return 1
}

true()
{
	return 0
}

phelp()
{
echo "$name: do a $cmd with extra checking and options.
$Usage
$name is used as a front end for $cmd to get the [icfo] options, and so
that a trailing / will force the last component of the path to be
interpreted as a directory, so that   $name foo bar/   will fail if bar is
not an existing directory, instead of changing the name of foo to bar. 
Effectively,  $name foo bar/   is short for  $name foo bar/foo
Options: 
-h prints this help.
-c checks first for the existence of each file, and fails if it exists.
-i is like -c except that if the file exists and stdin and stdout are a
   tty, a query is printed and a reply is read; a file is overwritten only
   if the reply begins with 'y'.
-f unsets -c and -i (in case $cmd is aliased to $name).
-o (overwrite only) checks that the named file(s) exist and fails for any
   that do not.  It is the complement of the -c option.
Whichever of [cifo] comes later on the command line determines the behaviour.
Any of these options must come before any standard $cmd options."
}

# interactive: Attempt to overwrite file should result in interactive
# query rather than automatic failure.
# noover: Do not overwrite files (if interactive is true, query, else fail)
# overwrite: Only overwriting is allowed, not creation of new files.
# debug: Print debugging info.
typeset interactive=false noover=false overwrite=false debug=false
name=${0##*/}

case "$name" in
ncp|nmv) cmd=/bin/${name#?} ;;
*) echo "$name: Must be invoked as ncp or nmv." 1>&2 ; exit 2;;
esac

Usage="Usage: $name [-cfhio] $cmd-cmd-line"

while getopts :cfhiox opt; do
    case $opt in
    h) phelp; exit 0;;
    x) debug=true ;;
    c) noover=true ;;
    i) noover=true ; interactive=true ;;
    f) noover=false ; interactive=false ;;
    o) overwrite=true ; noover=false ; interactive=false;;
    +?) echo "$name: options should not be preceded by a '+'." 1>&2; exit 2;;
    ?)  echo "$name: $OPTARG: bad option.  Use -h for help." 1>&2 ; exit 2;;
    esac
done
 
# remove args that were options
shift $((OPTIND - 1))

if [ $# -lt 2 ]; then
    echo -e "$Usage\nUse -h for help."
    exit
fi

Check()
{
    if [ ! -f "$1" ] && $overwrite; then
	echo "$name: $1: File does not exist." 1>&2
	return 1
    elif [ -f "$1" ] && $noover; then
	if [ $interactive = false ] || [ ! -t 0 ] || [ ! -t 1 ]; then
	    echo "$name: $1: File exists." 1>&2
	    return 1
	else
	    while :; do
		echo -n \
"$name: $1: File exists.  Overwrite? (y)es/(n)o/(a)bort/(Y)es for all: " 1>&2
		read reply
		case "$reply" in
		y*)
		    echo "$name: Overwriting $1."
		    return 0
		    ;;
		Y*)
		    echo "$name: Overwriting $1."
		    interactive=false
		    noover=false
		    return 0
		    ;;
		[nN]*)
		    echo "$name: Skipping $2."
		    return 1
		    ;;
		[aA]*)
		    echo "$name: Aborting."
		    exit 1
		    ;;
		*)
		    echo "$name: Invalid response." 1>&2
		    ;;
		esac
	    done
	fi
    else
	return 0
    fi
}

# i is the index of the filename being examined
# lastarg is the index of the last filename before the dest directory name
typeset -i i=0 lastarg=$(($#-1))

# Sets argv[0..$#-1]
argv=("$@")
$debug && echo argv = "${argv[@]}" 1>&2
dest=${argv[lastarg]}

if $debug; then
    echo \
"interactive=$interactive noover=$noover overwrite=$overwrite debug=$debug
lastarg=$lastarg dest=$dest name=$name cmd=$cmd
files=$*" 1>&2
fi

if $noover || $overwrite; then
    $debug && echo "checking for existance of directories..." 1>&2
    # If the destination is not intended to be a directory...
    if [ $# -eq 2 ] && [ ! -d "$dest" ]; then
	Check "$dest" "$1" || exit 0		# No files to copy
    else
	while [ $i -lt $lastarg ]; do
	    Check "$dest/${argv[i]##*/}" "${argv[i]}" || unset argv[i]
	    let i+=1
	done
    fi
fi

[ ${#argv[@]} -lt 2 ] && exit 0

# If only 2 args are given, mv/cp will not insist that the destination
# be a directory, which we want if the destination ends in "/" or if
# the original number of args was >2.
# $# is still the original number of args.
# Tack the file name onto the destination to force this behaviour.

lastisslash()
{
	case "$1" in
	*/)	return 0;;
	*)	return 1;;
	esac
}

if [ ${#argv[@]} = 2 ] && { lastisslash "$2" || [ $# -gt 2 ]; }; then
    $debug && echo "Appending filename." 1>&2
    # Don't know which element of argv[] holds the source filename, 
    # since may have started with more than 1 source file & had some unset.
    # So, compact args to make it easy to find the set one.
    argv=("${argv[@]}")
    argv[1]="${argv[1]}/${argv[0]##*/}"
fi

$debug && echo "Executing command: $cmd ${argv[@]}" 1>&2
exec $cmd "${argv[@]}"