如何驗證我的 bash 腳本以顯示在提示用戶時只能輸入 2 個文件名或使用 echo 語句出錯

Question

#!/bin/bash # Ask for user to enter two filenames echo Please Provide 2 filenames to compare read file1 file2 # Check to see if 2 different filenames are not provided

Answer 1

echo "Please Provide 2 filenames to compare"

read file1 file2
if [ "$file1" == "$file2" ]
then
  echo "ERROR: file names must be different."
  exit 1
fi

echo "Good stuff!"
# Bash returns result of "echo" function here, which is 0 (success)

Answer 2

bash

#!/usr/bin/env bash

while read -rp 'Please enter 2 filenames to compare: ' -a file; do
  if ! (( ${#file[*]} == 2 )); then
    printf >&2 'You entered %s file, need 2 files, please try again!\n' "${#file[*]}"
  elif [[ ${file[0]} == ${file[1]} ]]; then
    printf >&2 'Both %s and %s are the same, please try again!\n' "${file[0]}" "${file[1]}"
  elif ! [[ -e ${file[0]} && -e ${file[1]} ]]; then
    printf >&2 'Either one or both of the given file does not exists, please try again!%s\n'
  else
    printf 'All ok!\n' && break
  fi
done

printf 'You entered %s and %s\n' "${file[@]}"

• 循環繼續，直到滿足條件才退出腳本。

• 第一個條件，如果文件小於或大於 2。

• 第二個條件，如果兩個文件相同（相同的文件名）。

• 第三個條件，如果兩個或一個文件不存在。

• 如果在不滿足其中一個條件時需要退出腳本，請在elif （所有這些）塊內添加一個exit 1 ，在printf語句所在的行下方/之后。