在shell中，使用test命令和[]条件表达式可以测试各种文件属性。

shell判断文件是否存在 -a file

如果文件存在，则为true

示例

[ -a /etc/resolv.conf ] && echo "File found" || echo "Not found"

shell判断文件是否存在并且是否为块设备文件 -b file

如果文件存在并且是块设备文件，则为true

示例

[ -b /dev/zero ] && echo "block special file found" || echo "block special file not found"
[ -b /dev/sdb ] && echo "block special file found" || echo "block special file not found"

shell判断文件是否存在并且是否为字符设备文件 -c file

如果文件存在且为字符设备文件，则为true

示例

[ -c /dev/tty0  ] && echo "Character special file found." || echo "Character special file not found."

shell如何判断目录是否存在 -d dir

如果dir是目录并且存在，则为true

示例

#!/bin/bash
DEST="/backup"

# 如果目录不存在，则创建
[ ! -d "$DEST" ] && mkdir -p "$DEST"

shell判断文件是否存在 -e file

如果文件存在，则为true

示例

[ -e /tmp/test.txt ] && echo "File found" || echo "File not found"

shell判断文件是否为普通文件 -f file

如果文件存在并且是普通文件，则为true

示例

[ ! -f /path/to/file ] && echo "File not found!"

shell判断文件是否为链接 -h file

如果文件是链接文件，则为true

示例

[ -r /etc/resolv.conf ] && echo "File is a symbolic link" || echo " The file is not a symbolic link"

shell判断文件是否为命名管道 -p file

如果是命名管道，则为true

示例

[ -r /etc/resolv.conf ] && echo "File is a named pipe" || echo " The file is not a named pipe"

shell判断文件是否可读 -r file

如果文件可读，则为true

示例

[ -r /etc/resolv.conf ] && echo "File is readable" || echo "is Not  readable"

shell判断文件是否可写 -w file

如果文件可写，则为true

示例

[ -w /etc/resolv.conf ] && echo "File is writable" || echo "is Not  writable"

shell判断文件是否可执行 -x file

如果文件有可执行权限，则为true

示例

[ -x /etc/resolv.conf ] && echo "File is executable" || echo "is Not  executable"

shell判断文件大小是否大于0 -s file

如果文件大小大于0，则为true

示例

[ -s /path/to/file ] && echo "File size >0 !"

shell判断文件是否为socket -S file

如果文件是socket，则为true

示例

[ -r /etc/resolv.conf ] && echo "File is a socket" || echo " The file is not a socket "