Question

我正在编写一个shell脚本，通过用户输入读取give目录中的所有文件，然后计算具有该扩展名的文件数。我刚刚开始学习Bash，我不确定为什么它不能找到文件或读取目录。我只提了两个例子，但我的计数总是0。

这是我运行脚本的方式

$./check_ext.sh /home/user/temp

我的脚本check_ext.sh

#!/bin/bash

count1=0
count2=0

for file in "ls $1"
do
if [[ $file == *.sh ]]; then 
    echo "is a txt file"
    (( count1++ ))
elif [[ $file == *.mp3 ]]; then
    echo "is a mp3 file"
    (( count2++ ))
fi  
done;

echo $count $count2

Answer 1

"ls $1"不会在ls上执行$1，它只是一个纯字符串。命令替换语法为$(ls "$1")

但是没有必要使用ls，只需使用globbing：

count1=0
count2=0

for file in "$1"/*; do
   if [[ $file == *.sh ]]; then 
       echo "is a txt file"
       (( count1++ ))
   elif [[ $file == *.mp3 ]]; then
       echo "is a mp3 file"
       (( count2++ ))
   fi  
done

echo "counts: $count1 $count2"

for file in "$1"/*将遍历$1

编辑：在目录中递归执行：

count1=0
count2=0

while IFS= read -r -d '' file; do
   if [[ $file == *.sh ]]; then 
       echo "is a txt file"
       (( count1++ ))
   elif [[ $file == *.mp3 ]]; then
       echo "is a mp3 file"
       (( count2++ ))
   fi  
done < <(find "$1" -type f -print0)

echo "counts: $count1 $count2"

Answer 2

POSIXly：

count1=0
count2=0

for f in "$1"/*; do
  case $f in
     (*.sh) printf '%s is a txt file\n' "$f"; : "$((count1+=1))" ;;
    (*.mp3) printf '%s is a mp3 file\n' "$f"; : "$((count2+=1))" ;;
  esac
done

printf 'counts: %d %d\n' "$count1" "$count2"

Answer 3

您也可以使用Bash数组：如果您只想处理扩展程序sh和mp3：

#!/bin/bash

shopt -s nullglob

shs=( "$1"/*.sh )
mp3s=( "$1"/*.mp3 )

printf 'counts: %d %d\n' "${#shs[@]}" "${#mp3s[@]}"

如果您想处理更多扩展程序，可以概括此过程：

#!/bin/bash

shopt -s nullglob

exts=( .sh .mp3 .gz .txt )
counts=()

for ext in "${exts[@]}"; do
    files=( "$1"/*."$ext" )
    counts+=( "${#files[@]}" )
done

printf 'counts:'
printf ' %d' "${counts[@]}"
echo

如果你想处理所有扩展（使用关联数组，可以在Bash中使用≥4）

#!/bin/bash

shopt -s nullglob

declare -A exts

for file in "$1"/*.*; do
    ext=${file##*.}
    ((++'exts[$ext]'))
done

for ext in "${!exts[@]}"; do
    printf '%s: %d\n' "$ext" "${exts[$ext]}"
done

bash检查目录中的所有文件的扩展名

3 个答案: