-xFILE- True if the FILE exists and is executable. Conclusion In this guide, we have shown you how to check if a file or directory exists in Bash. You can find more information about thetestcommand by typingman testinto your terminal. ...
How do I check if a file is empty in Bash? You can use the find command and other options as follows. The -s option to the test builtin check to see if FILE exists and has a size greater than zero. It returns true and false values to indicate that file is empty or has some da...
Shell脚本应用(if语句的应用示例) 一、条件测试操作 1、文件测试(1)测试目录/media是否为目录,$?返回值为0,表示存在此目录。如果$?返回值非0,表示不存在此目录(2)测试目录是否存在,输出结果更加直观。输出“yes” 06 21.shell语言之if条件判断语句 then后面跟符合条件之后执行的程序,可以放在[]之后,用;分隔。
Manual pages cover the essentials, but there are many more ways to get online help. If you’re just looking for a certain option for a command, try entering a command name followed by --help or -h (the option varies from command to command). You may get a deluge (as in the case ...
if [ condition ] then command1 command2 ... else command3 command4 ... fi 例如,以下代码判断当前目录下是否存在一个名为file.txt的文件: # 判断当前目录下是否存在一个名为file.txt的文件,图方便写成一行。 if [ -f file.txt ]; then echo "file.txt exists."; else echo "file.txt does not...
#Take the filename from the command-line argument filename=$1 #Check whether the argument is missing or not if["$filename"!=""];then #Check whether the file exists or not using the -f operator if[[-f"$filename"]];then echo"File exists." ...
yum的命令形式一般是如下:yum [options] [command] [package ...] 其中的[options]是可选的,选项包括-h(帮助),-y(当安装过程提示选择全部为"yes"),-q(不显示安装的过程)等等。[command]为所要进行的操作,[package ...]是操作的对象。 概括了部分常用的命令包括: ...
if condition_command then echo "Condition is true" else echo "Condition is false" fi 4. Check whether a [f]ile exists: if [[ -f path/to/file ]] then echo "Condition is true" fi 5. Check whether a [d]irectory exists: if [[ -d path/to/directory ]] ...
"" if retCode == 0 or os.path.ismount(targetPath): retCode = 0 break maxRetry = maxRetry - 1 time.sleep(1) return retCode """Run command facilities.""" if not hasattr(subprocess,'check_output'): def check_output(*popenargs, **kwargs): r"""Backport from subprocess module from ...
1. 使用if-else语句 使用if-else语句可以根据条件执行不同的命令。语法如下: “` if condition then command1 else command2 fi “` 示例: “` if [ $var -eq 0 ] then echo “var等于0” else echo “var不等于0” fi “` 上述示例中,如果变量`var`等于0,则输出`var等于0`,否则输出`var不等于0...