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331 lines
8.9 KiB
Markdown
331 lines
8.9 KiB
Markdown
[#]: collector: (lujun9972)
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[#]: translator: (wxy)
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[#]: reviewer: (wxy)
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[#]: publisher: (wxy)
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[#]: url: (https://linux.cn/article-12025-1.html)
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[#]: subject: (Try this Bash script for large filesystems)
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[#]: via: (https://opensource.com/article/20/2/script-large-files)
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[#]: author: (Nick Clifton https://opensource.com/users/nickclifton)
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针对大型文件系统可以试试此 Bash 脚本
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======
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> 一个可以列出文件、目录、可执行文件和链接的简单脚本。
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![bash logo on green background][1]
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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。
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当然，你可以使用 `find` 命令：
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```
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find . -maxdepth 1 -type f -print
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```
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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：
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```
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ls -F . | grep -v /
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```
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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。
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### 用法
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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。
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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。
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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：
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```
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lsf -a
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```
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要以长格式列出目录，请使用 `lsd` 命令：
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```
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lsd -l
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```
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你可以提供多个参数，以及文件和目录路径。
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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：
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```
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lsf -F -l .. /usr/bin
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```
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目前该脚本不处理递归，仅列出当前目录中的文件。
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```
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lsf -R
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```
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该脚本不会深入子目录，这个不足有一天可能会进行修复。
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### 内部
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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。
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`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。
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### 总结
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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。
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### 脚本
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```
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#!/bin/bash
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# Script to list:
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# directories (if called "lsd")
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# files (if called "lsf")
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# links (if called "lsl")
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# or executables (if called "lsx")
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# but not any other type of filesystem object.
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# FIXME: add lsp (list pipes)
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#
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# Usage:
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# <command_name> [switches valid for ls command] [dirname...]
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#
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# Works with names that includes spaces and that start with a hyphen.
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#
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# Created by Nick Clifton.
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# Version 1.4
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# Copyright (c) 2006, 2007 Red Hat.
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#
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# This is free software; you can redistribute it and/or modify it
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# under the terms of the GNU General Public License as published
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# by the Free Software Foundation; either version 3, or (at your
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# option) any later version.
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# It is distributed in the hope that it will be useful, but
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# WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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# ToDo:
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# Handle recursion, eg: lsl -R
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# Handle switches that take arguments, eg --block-size
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# Handle --almost-all, --ignore-backups, --format and --ignore
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main ()
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{
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init
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parse_args ${1+"$@"}
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list_objects
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exit 0
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}
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report ()
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{
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echo $prog": " ${1+"$@"}
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}
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fail ()
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{
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report " Internal error: " ${1+"$@"}
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exit 1
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}
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# Initialise global variables.
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init ()
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{
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# Default to listing things in the current directory.
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dirs[0]=".";
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# num_dirs is the number of directories to be listed minus one.
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# This is because we are indexing the dirs[] array from zero.
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num_dirs=0;
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# Default to ignoring things that start with a period.
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no_dots=1
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# Note - the global variables 'type' and 'opts' are initialised in
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# parse_args function.
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}
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# Parse our command line
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parse_args ()
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{
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local no_more_args
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no_more_args=0 ;
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prog=`basename $0` ;
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# Decide if we are listing files or directories.
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case $prog in
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lsf | lsf.sh)
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type=f
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opts="";
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;;
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lsd | lsd.sh)
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type=d
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# The -d switch to "ls" is presumed when listing directories.
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opts="-d";
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;;
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lsl | lsl.sh)
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type=l
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# Use -d to prevent the listed links from being followed.
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opts="-d";
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;;
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lsx | lsx.sh)
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type=f
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find_extras="-perm /111"
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;;
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*)
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fail "Unrecognised program name: '$prog', expected either 'lsd', 'lsf', 'lsl' or 'lsx'"
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;;
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esac
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# Locate any additional command line switches for ls and accumulate them.
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# Likewise accumulate non-switches to the directories list.
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while [ $# -gt 0 ]
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do
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case "$1" in
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# FIXME: Handle switches that take arguments, eg --block-size
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# FIXME: Properly handle --almost-all, --ignore-backups, --format
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# FIXME: and --ignore
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# FIXME: Properly handle --recursive
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-a | -A | --all | --almost-all)
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no_dots=0;
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;;
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--version)
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report "version 1.2"
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exit 0
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;;
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--help)
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case $type in
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d) report "a version of 'ls' that lists only directories" ;;
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l) report "a version of 'ls' that lists only links" ;;
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f) if [ "x$find_extras" = "x" ] ; then
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report "a version of 'ls' that lists only files" ;
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else
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report "a version of 'ls' that lists only executables";
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fi ;;
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esac
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exit 0
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;;
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--)
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# A switch to say that all further items on the command line are
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# arguments and not switches.
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no_more_args=1 ;
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;;
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-*)
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if [ "x$no_more_args" = "x1" ] ;
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then
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dirs[$num_dirs]="$1";
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let "num_dirs++"
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else
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# Check for a switch that just uses a single dash, not a double
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# dash. This could actually be multiple switches combined into
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# one word, eg "lsd -alF". In this case, scan for the -a switch.
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# XXX: FIXME: The use of =~ requires bash v3.0+.
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if [[ "x${1:1:1}" != "x-" && "x$1" =~ "x-.*a.*" ]] ;
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then
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no_dots=0;
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fi
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opts="$opts $1";
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fi
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;;
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*)
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dirs[$num_dirs]="$1";
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let "num_dirs++"
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;;
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esac
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shift
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done
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# Remember that we are counting from zero not one.
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if [ $num_dirs -gt 0 ] ;
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then
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let "num_dirs--"
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fi
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}
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list_things_in_dir ()
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{
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local dir
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# Paranoia checks - the user should never encounter these.
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if test "x$1" = "x" ;
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then
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fail "list_things_in_dir called without an argument"
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fi
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if test "x$2" != "x" ;
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then
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fail "list_things_in_dir called with too many arguments"
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fi
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# Use quotes when accessing $dir in order to preserve
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# any spaces that might be in the directory name.
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dir="${dirs[$1]}";
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# Catch directory names that start with a dash - they
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# confuse pushd.
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if test "x${dir:0:1}" = "x-" ;
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then
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dir="./$dir"
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fi
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if [ -d "$dir" ]
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then
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if [ $num_dirs -gt 0 ]
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then
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echo " $dir:"
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fi
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# Use pushd rather passing the directory name to find so that the
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# names that find passes on to xargs do not have any paths prepended.
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pushd "$dir" > /dev/null
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if [ $no_dots -ne 0 ] ; then
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find . -maxdepth 1 -type $type $find_extras -not -name ".*" -printf "%f\000" \
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| xargs --null --no-run-if-empty ls $opts -- ;
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else
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find . -maxdepth 1 -type $type $find_extras -printf "%f\000" \
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| xargs --null --no-run-if-empty ls $opts -- ;
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fi
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popd > /dev/null
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else
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report "directory '$dir' could not be found"
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fi
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}
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list_objects ()
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{
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local i
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i=0;
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while [ $i -le $num_dirs ]
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do
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list_things_in_dir i
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let "i++"
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done
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}
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# Invoke main
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main ${1+"$@"}
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```
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--------------------------------------------------------------------------------
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via: https://opensource.com/article/20/2/script-large-files
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作者：[Nick Clifton][a]
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选题：[lujun9972][b]
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译者：[wxy](https://github.com/wxy)
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校对：[wxy](https://github.com/wxy)
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本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
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[a]: https://opensource.com/users/nickclifton
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[b]: https://github.com/lujun9972
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[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/bash_command_line.png?itok=k4z94W2U (bash logo on green background)
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