一举测试多个文件条件(BASH)? [英] Test multiple file conditions in one swoop (BASH)?

问题描述

在为 bash shell 编写代码时，通常需要测试文件(或目录)是否存在(或不存在)并采取适当的措施.这些测试中最常见的是...

Often when writing for the bash shell, one needs to test if a file (or Directory) exists (or doesn't exist) and take appropriate action. Most common amongst these test are...

-e - 文件存在，-f - 文件是一个普通文件(不是目录或设备文件)，-s -文件不是零大小，-d - 文件是一个目录，-r - 文件有读权限，-w - 文件有写，或 -x 执行权限(针对运行测试的用户)

-e - file exists, -f - file is a regular file (not a directory or device file), -s - file is not zero size, -d - file is a directory, -r - file has read permission, -w - file has write, or -x execute permission (for the user running the test)

正如在此用户可写目录中所示，这很容易确认....

This is easily confirmed as demonstrated on this user-writable directory....

#/bin/bash

if [ -f "/Library/Application Support" ]; then
echo 'YES SIR -f is fine'
else echo 'no -f for you'
fi

if [ -w "/Library/Application Support" ]; then
echo 'YES SIR -w is fine'
else echo 'no -w for you'
fi

if [ -d "/Library/Application Support" ]; then
echo 'YES SIR -d is fine'
else echo 'no -d for you'
fi

➝ 没有 -f 给你 ✓
➝ 是的 SIR -w 很好 ✓
➝ 是的 SIR -d 很好 ✓

我的问题，虽然看起来很明显，也不太可能是不可能的 - 是如何简单地组合这些测试，而不必为每个条件单独执行它们......不幸的是......

My question, although seemingly obvious, and unlikely to be impossible - is how to simply combine these tests, without having to perform them separately for each condition... Unfortunately...

if [ -wd "/Library/Application Support" ]  
  ▶  -wd: unary operator expected

if [ -w | -d "/Library/Application Support" ]   
  ▶  [: missing `]'
  ▶  -d: command not found

if [ -w [ -d "/Library.... ]]   &  if [ -w && -d "/Library.... ] 
  ▶  [: missing `]'

➝ 没有 -wd 给你 ✖
➝ 没有 -w |-d 给你 ✖
➝ 没有 [ -w [ -d .. ]] 给你 ✖
➝ 没有 -w &&-d 给你 ✖

我在这里错过了什么?

推荐答案

您可以对多个条件使用逻辑运算符，例如-a 用于 AND:

You can use logical operators to multiple conditions, e.g. -a for AND:

MYFILE=/tmp/data.bin
if [ -f "$MYFILE"  -a  -r "$MYFILE"  -a  -w "$MYFILE" ]; then
    #do stuff
fi
unset MYFILE

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