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  • 如何判断某个设备文件是否存在

    问:如何在shell里面实现,判断设备文件是否存在,如果不存在则重新判断,直到它存在,如果存在了则往下跑?

    假设要判断的设备文件是一个字符设备,例如:/dev/input/event4

    while true; do
    	if [ ! -c /dev/input/event4 ]; then
    		echo "Can not find /dev/input/event4"
    		sleep 1
    		continue
    	else 
    		echo "Found /dev/input/event$event_num"
    		do something
    		break
    	fi
    done 


    另外,附上shell  if 语言常用的参数说明

    -a file exists. 
    -b file exists and is a block special file. 
    -c file exists and is a character special file. 
    -d file exists and is a directory. 
    -e file exists (just the same as -a). 
    -f file exists and is a regular file. 
    -g file exists and has its setgid(2) bit set. 
    -G file exists and has the same group ID as this process. 
    -k file exists and has its sticky bit set. 
    -L file exists and is a symbolic link. 
    -n string length is not zero. 
    -o Named option is set on. 
    -O file exists and is owned by the user ID of this process. 
    -p file exists and is a first in, first out (FIFO) special file or 
    named pipe. 
    -r file exists and is readable by the current process. 
    -s file exists and has a size greater than zero. 
    -S file exists and is a socket. 
    -t file descriptor number fildes is open and associated with a 
    terminal device. 
    -u file exists and has its setuid(2) bit set. 
    -w file exists and is writable by the current process. 
    -x file exists and is executable by the current process. 
    -z string length is zero. 

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  • 原文地址:https://www.cnblogs.com/zhangyunlin/p/6167904.html
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