if stat "/path/to/file" >/dev/null 2>&1; then echo "File exists." else echo "File...
在Bash Shell中,可以使用复合条件来在一个if语句中检查多个条件。复合条件主要有两种形式:逻辑与(&&)和逻辑或(||)。 1. 逻辑与(&&): - 概念:逻辑与用于同时检查多个条件...
if!type"$foobar_command_name"> /dev/null;then# install foobar here,or poping up some warning messagesfi references: http://stackoverflow.com/questions/7522712/how-to-check-if-command-exists-in-a-shell-script http://stackoverflow.com/questions/592620/how-to-check-if-a-program-exists-from-a...
[root@Centos8_test bashpractise]# cat lib01.sh_checkFileExists(){if[-f$1]thenecho"File:$1exists"elseecho"File:$1not exists"fi} 其他脚本在希望直接调用_checkFileExists函数时,可以通过直接加载lib01.sh函数库的方式实现。加载方式有以下两种: #使用“点”命令[root@localhost ~]# . /PATH/...
Catkin tools installed successfully."fi}create_catkin_ws(){# Checkifworkspace existsif[ -e"$CATKIN_DIR/.catkin_workspace"] || [ -d"$CATKIN_DIR/.catkin_tools"]; thenecho"Catkin workspace detected at ~/catkin_ws"elseecho"Creating catkin workspace ...
How to check if a directory exists? How to check if a command succeeds or failed? How to do string comparison and check if a string equals to a value? How to check if a string is in an array? How to use the Bash ternary operator? How to negate an if condition in a Bash if sta...
f FILE—— 如果 ref="https://linuxize.com/post/bash-check-if-file-exists/">FILE 存在,并且是常规文件(不是目录或设备什么的) ,则为真。 结论 if、if..else 和if..elif..else 语句让我们能够基于不同的判断条件来控制 Bash 脚本中逻辑语句的执行。 如果你有任何疑问或反馈,请随时发表评论。
Similarly for example we can use while loop to check if file does not exists. This script will sleep until file does exists. Note bash negator "!" which negates the -e option. #!/bin/bash while [ ! -e myfile ]; do # Sleep until file does exists/is created ...
This is the job of the test command, which can check if a file exists and its type. Since only the check is completed, the test command sets the exit code to 0 or 1 (either false or true, respectively) whether the test is successful or not. ...
使用bash,检查变量是否为空的最佳方法是什么?if [ -z "$VAR" ] 正如论坛中建议的那样,这适用于未设置的变量,但当变量已设置但为空时,这是正确的。有什么建议吗? 浏览4提问于2011-03-23得票数 12 回答已采纳 1回答 将变量名称传递到函数中,以测试是否存在和不为空。 ( A)我是初出茅庐# check if con...