2020-03-19 21:49:36 +08:00
[#]: collector: (lujun9972)
[#]: translator: (wxy)
[#]: reviewer: (wxy)
2020-03-23 09:51:59 +08:00
[#]: publisher: (wxy)
[#]: url: (https://linux.cn/article-12025-1.html)
2020-03-19 21:49:36 +08:00
[#]: subject: (Try this Bash script for
[#]: via: (https://opensource.com/article/20/2/script-large-files)
[#]: author: (Nick Clifton https://opensource.com/users/nickclifton)
针对大型文件系统可以试试此 Bash 脚本
======
> 一个可以列出文件、目录、可执行文件和链接的简单脚本。
![bash logo on green background][1]
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:
# <command_name> [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]=".";
# num_dirs is the number of directories to be listed minus one.
# This is because we are indexing the dirs[] array from zero.
num_dirs=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
parse_args ()
{
local no_more_args
no_more_args=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)
no_dots=0;
;;
--version)
report "version 1.2"
exit 0
;;
--help)
case $type in
d) report "a version of 'ls' that lists only directories" ;;
l) report "a version of 'ls' that lists only links" ;;
f) if [ "x$find_extras" = "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.
no_more_args=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$1" =~ "x-.*a.*" ]] ;
then
no_dots=0;
fi
opts="$opts $1";
fi
;;
*)
dirs[$num_dirs]="$1";
let "num_dirs++"
;;
esac
shift
done
# Remember that we are counting from zero not one.
if [ $num_dirs -gt 0 ] ;
then
let "num_dirs--"
fi
}
list_things_in_dir ()
{
local dir
# Paranoia checks - the user should never encounter these.
if test "x$1" = "x" ;
then
fail "list_things_in_dir called without an argument"
fi
if test "x$2" != "x" ;
then
fail "list_things_in_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 $num_dirs ]
do
list_things_in_dir i
let "i++"
done
}
# Invoke main
main ${1+"$@"}
```
--------------------------------------------------------------------------------
via: https://opensource.com/article/20/2/script-large-files
作者：[Nick Clifton][a]
选题：[lujun9972][b]
译者：[wxy](https://github.com/wxy)
校对：[wxy](https://github.com/wxy)
本文由 [LCTT ](https://github.com/LCTT/TranslateProject ) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://opensource.com/users/nickclifton
[b]: https://github.com/lujun9972
[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)
