針對大型檔案系統可以試試此 Bash 指令碼

一個可以列出檔案、目錄、可執行檔案和連結的簡單指令碼。

你是否曾經想列出目錄中的所有檔案，但僅列出檔案，而不列出其它的。僅列出目錄呢？如果有這種需求的話，那麼下面的指令碼可能正是你一直在尋找的，它在 GPLv3 下開源。

當然，你可以使用 find 命令：

find . -maxdepth 1 -type f -print

但這鍵入起來很麻煩，輸出也不友好，並且缺少 ls 命令擁有的一些改進。你還可以結合使用 ls 和 grep 來達到相同的結果：

ls -F . | grep -v /

但是，這又有點笨拙。下面這個指令碼提供了一種簡單的替代方法。

用法

該指令碼提供了四個主要功能，具體取決於你呼叫它的名稱：lsf 列出檔案，lsd 列出目錄，lsx 列出可執行檔案以及 lsl 列出連結。

通過符號連結無需安裝該指令碼的多個副本。這樣可以節省空間並使指令碼更新更容易。

該指令碼通過使用 find 命令進行搜尋，然後在找到的每個專案上執行 ls。這樣做的好處是，任何給指令碼的引數都將傳遞給 ls 命令。因此，例如，這可以列出所有檔案，甚至包括以點開頭的檔案：

lsf -a

要以長格式列出目錄，請使用 lsd 命令：

lsd -l

你可以提供多個引數，以及檔案和目錄路徑。

下面提供了當前目錄的父目錄和 /usr/bin 目錄中所有檔案的長分類列表：

lsf -F -l .. /usr/bin

目前該指令碼不處理遞迴，僅列出當前目錄中的檔案。

lsf -R

該指令碼不會深入子目錄，這個不足有一天可能會進行修復。

內部

該指令碼採用自上而下的方式編寫，其初始化功能位於指令碼的開頭，而工作主體則接近結尾。指令碼中只有兩個真正重要的功能。函式 parse_args() 會仔細分析命令列，將選項與路徑名分開，並處理指令碼中的 ls 命令列選項中的特定選項。

list_things_in_dir() 函式以目錄名作為引數並在其上執行 find 命令。找到的每個專案都傳遞給 ls 命令進行顯示。

總結

這是一個可以完成簡單功能的簡單指令碼。它節省了時間，並且在使用大型檔案系統時可能會非常有用。

指令碼

#!/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 選題：lujun9972 譯者：wxy 校對：wxy

本文由 LCTT 原創編譯，Linux中國 榮譽推出

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