一个可以列出文件、目录、可执行文件和链接的简单脚本。

你是否曾经想列出目录中的所有文件，但仅列出文件，而不列出其它的。仅列出目录呢？如果有这种需求的话，那么下面的脚本可能正是你一直在寻找的，它在 GPLv3 下开源。

当然，你可以使用 find 命令：


find . -maxdepth 1 -type f -print


但这键入起来很麻烦，输出也不友好，并且缺少 ls 命令拥有的一些改进。你还可以结合使用 ls 和 grep 来达到相同的结果：


ls -F . | grep -v /


但是，这又有点笨拙。下面这个脚本提供了一种简单的替代方法。

用法

该脚本提供了四个主要功能，具体取决于你调用它的名称：lsf 列出文件，lsd 列出目录，lsx 列出可执行文件以及 lsl 列出链接。

通过符号链接无需安装该脚本的多个副本。这样可以节省空间并使脚本更新更容易。

该脚本通过使用 find 命令进行搜索，然后在找到的每个项目上运行 ls。这样做的好处是，任何给脚本的参数都将传递给 ls 命令。因此，例如，这可以列出所有文件，甚至包括以点开头的文件：


lsf -a


要以长格式列出目录，请使用 lsd 命令：


lsd -l


你可以提供多个参数，以及文件和目录路径。

下面提供了当前目录的父目录和 /usr/bin 目录中所有文件的长分类列表：


lsf -F -l .. /usr/bin


目前该脚本不处理递归，仅列出当前目录中的文件。


lsf -R


该脚本不会深入子目录，这个不足有一天可能会进行修复。

内部

该脚本采用自上而下的方式编写，其初始化功能位于脚本的开头，而工作主体则接近结尾。脚本中只有两个真正重要的功能。函数 parse_args() 会仔细分析命令行，将选项与路径名分开，并处理脚本中的 ls 命令行选项中的特定选项。

list_things_in_dir() 函数以目录名作为参数并在其上运行 find 命令。找到的每个项目都传递给 ls 命令进行显示。

总结

这是一个可以完成简单功能的简单脚本。它节省了时间，并且在使用大型文件系统时可能会非常有用。

脚本

“`

!/bin/bash

Script to list:

directories (if called “lsd”)

files (if called “lsf”)

links (if called “lsl”)

or executables (if called “lsx”)

but not any other type of filesystem object.

FIXME: add lsp (list pipes)

#

Usage:

[switches valid for ls command] [dirname…]

#

Works with names that includes spaces and that start with a hyphen.

#

Created by Nick Clifton.

Version 1.4

Copyright (c) 2006, 2007 Red Hat.

#

This is free software; you can redistribute it and/or modify it

under the terms of the GNU General Public License as published

by the Free Software Foundation; either version 3, or (at your

option) any later version.

It is distributed in the hope that it will be useful, but

WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

GNU General Public License for more details.

ToDo:

Handle recursion, eg: lsl -R

Handle switches that take arguments, eg –block-size

Handle –almost-all, –ignore-backups, –format and –ignore

main ()
{
init

parse_args ${1+”$@”}

list_objects

exit 0
}

report ()
{
echo $prog”: ” ${1+”$@”}
}

fail ()
{
report ” Internal error: ” ${1+”$@”}
exit 1
}

Initialise global variables.

init ()
{
# Default to listing things in the current directory.
dirs[0]=”.”;

# numdirs is the number of directories to be listed minus one.
# This is because we are indexing the dirs[] array from zero.
numdirs=0;

# Default to ignoring things that start with a period.
no_dots=1

# Note – the global variables ‘type’ and ‘opts’ are initialised in
# parse_args function.
}

Parse our command line

parseargs ()
{
local nomore_args

nomoreargs=0 ;

prog=basename $0 ;

# Decide if we are listing files or directories.
case $prog in
lsf | lsf.sh)
type=f
opts=””;
;;
lsd | lsd.sh)
type=d
# The -d switch to “ls” is presumed when listing directories.
opts=”-d”;
;;
lsl | lsl.sh)
type=l
# Use -d to prevent the listed links from being followed.
opts=”-d”;
;;
lsx | lsx.sh)
type=f
find_extras=”-perm /111″
;;
*)
fail “Unrecognised program name: ‘$prog’, expected either ‘lsd’, ‘lsf’, ‘lsl’ or ‘lsx'”
;;
esac

# Locate any additional command line switches for ls and accumulate them.
# Likewise accumulate non-switches to the directories list.
while [ $# -gt 0 ]
do
case “$1” in
# FIXME: Handle switches that take arguments, eg –block-size
# FIXME: Properly handle –almost-all, –ignore-backups, –format
# FIXME: and –ignore
# FIXME: Properly handle –recursive
-a | -A | –all | –almost-all)
nodots=0;
;;
–version)
report “version 1.2”
exit 0
;;
–help)
case $type in
d) report “a version of ‘ls’ that lists only directories” ;;
l) report “a version of ‘ls’ that lists only links” ;;
f) if [ “x$findextras” = “x” ] ; then
report “a version of ‘ls’ that lists only files” ;
else
report “a version of ‘ls’ that lists only executables”;
fi ;;
esac
exit 0
;;
–)
# A switch to say that all further items on the command line are
# arguments and not switches.
nomoreargs=1 ;
;;
–)
if [ “x$no_more_args” = “x1″ ] ;
then
dirs[$num_dirs]=”$1”;
let “num_dirs++”
else
# Check for a switch that just uses a single dash, not a double
# dash. This could actually be multiple switches combined into
# one word, eg “lsd -alF”. In this case, scan for the -a switch.
# XXX: FIXME: The use of =~ requires bash v3.0+.
if [[ “x${1:1:1}” != “x-” && “x$1” =~ “x-.a.*” ]] ;
then
nodots=0;
fi
opts=”$opts $1″;
fi
;;
*)
dirs[$numdirs]=”$1″;
let “num_dirs++”
;;
esac
shift
done

# Remember that we are counting from zero not one.
if [ $numdirs -gt 0 ] ;
then
let “numdirs–”
fi
}

listthingsin_dir ()
{
local dir

# Paranoia checks – the user should never encounter these.
if test “x$1” = “x” ;
then
fail “listthingsin_dir called without an argument”
fi

if test “x$2” != “x” ;
then
fail “listthingsin_dir called with too many arguments”
fi

# Use quotes when accessing $dir in order to preserve
# any spaces that might be in the directory name.
dir=”${dirs[$1]}”;

# Catch directory names that start with a dash – they
# confuse pushd.
if test “x${dir:0:1}” = “x-” ;
then
dir=”./$dir”
fi

if [ -d “$dir” ]
then
if [ $num_dirs -gt 0 ]
then
echo ” $dir:”
fi

# Use pushd rather passing the directory name to find so that the
# names that find passes on to xargs do not have any paths prepended.
pushd "$dir" > /dev/null
if [ $no_dots -ne 0 ] ; then
  find . -maxdepth 1 -type $type $find_extras -not -name ".*" -printf "%f\000" \
    | xargs --null --no-run-if-empty ls $opts -- ;
else
  find . -maxdepth 1 -type $type $find_extras -printf "%f\000" \
    | xargs --null --no-run-if-empty ls $opts -- ;
fi
popd > /dev/null

else
report “directory ‘$dir’ could not be found”
fi
}

list_objects ()
{
local i

i=0;
while [ $i -le $numdirs ]
do
listthingsindir i
let “i++”
done
}

Invoke main

main ${1+”$@”}
“`

via: https://opensource.com/article/20/2/script-large-files

作者：Nick Clifton 选题：lujun9972 译者：wxy 校对：wxy

本文由 LCTT 原创编译，Linux中国 荣誉推出