UNIX入門課程1061_ex9

http://erdos.csie.ncnu.edu.tw/~klim/unix-intro/unix-intro-1061.html
作業九: listing a directory recursively
•建立一個 shell 執行檔, 名為 showdir, 可印出 類似用 tree -F 所得的結果.
若檔案為一目錄, 則在檔名後加 '/'
若檔案為一 symbolic link, 用箭頭顯示. 如上圖所示.
若目錄無法讀取內容, 則略過其以下的內容, 即只顯示目錄名字.
請勿用 find, du 或其他指令先得到一個 tree.

$./showdir /var/tmp/exer9-test-dir
exer9-test-dir/
|---city/
|   |---lapula --> ../sky/temple/utopia
|   `---rome
|---dogs/
`---sky/
    |---birds
    |---mountains
    `---temple/
        |---asking
        `---utopia

$ tree -F /var/tmp/exer9-test-dir
/var/tmp/exer9-test-dir
|-- city/
|   |-- lapula -> ../sky/temple/utopia
|   `-- rome
|-- dogs/
`-- sky/
    |-- birds
    |-- mountains
    `-- temple/
        |-- asking
        `-- utopia
     
4 directories, 6 files
$

解答:

#!/bin/bash
olddir=$PWD
dirdepth=0
function is_last_file {
  local flag
  let flag=${ary[dirdepth]}-1
    if [ $flag -eq 0 ]; then #last file
      ch="\\"  #as \---
    else
      ch="|"   #as |---
    fi
}
function print_file {
  is_last_file #check this file is last?
  case "$1" in
      -D) printf "$ch---$2/\n"
          ;; #file is directory
      -L) printf "$ch---$file --> "
          ls -l $file | awk '{ print $11 }'
          ;; #file is link
      -F) printf "$ch---$file\n" #normal file
          ;; #file is normal file
  esac
  let ary[dirdepth]=ary[dirdepth]-1
}
function check_file_type {
  if [ $dirdepth -gt 0 ]; then  
          for ((i=0; i<=dirdepth-1; i++)); do
            if [ ${ary[i]} -ne 0 ]; then
              printf "|   " #print | & 3 space
            else
              printf "    " #print 4 space
            fi
          done # for END
  fi
  if [ -d "$file" ]; then 
      print_file -D $file #directory  
  else          
      if [ -L $file ]; then
          print_file -L $file #symbolic link
      else 
          print_file -F $file #normal file
      fi
  fi
}
function listfiles {
  cd "$1";
    f_count=`ls -l | wc -l`  #calc total files 
    let f_count=f_count-1
    ary[dirdepth]=$f_count

  if [ $f_count -ne 0 ]; then # if dir is empty then exit
    for file in *; do
      check_file_type $file #call sub
      if [ -d "$file" ]; then
          let dirdepth=$dirdepth+1
          listfiles "$file"
          cd ..;
      fi
    done #for END
  fi
  let dirdepth=$dirdepth-1
}
#-----Main Program 2017/12/06 update-----
#d=$1
#echo "${d##*/}/"
echo "$(basename "$1")/"
listfiles "$1"
 

執行結果: