Navigate to a directory where your hello_world.sh is located and make the file executable: $ chmod +x hello_world.sh Now you are ready to execute your first bash script: ./hello_world.sh 2. Simple Backup bash s
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...
ln -s:link -soft创建一个软链接,相当于创建一个快捷方式 mkdir:Make Directory(创建目录) touch:touch man:Manual su:Swith user(切换用户) cd:Change directory ls:List files mkfs:Make file system fsck:File system check uname:Unix name lsmod:List modules mv:Move file cp:Copy file ln:Link files ...
Check if the directory still exists The -d operator allows you to test if a file is a directory. For example, to check if the /etc/filetocheck directory exists, you can use: NOTE: You can also use double brackets [[ instead of [ single brackets. Check if the file doesn’t exist ...
Check a file exists 1 2 3 4 5 6 7 1. 2. 3. 4. 5. 6. 7. #!/bin/bashif [[ -e /tmp/adb.log ]]then echo "Exists"else echo "Not Exists"fi 1. Check Empty String 1 2 3 4 5 6 1. 2. 3. 4. 5. 6. if [[ -z "$emptyString" ]]then echo "Empty"else echo "Not...
拖入浏览器,方可跳转到指定锚点https://www.gnu.org/software/bash/manual/bash.html#:~:text=%5D-,3.2.5.2%20Conditional%20Constructs,-if Shell 中test单中括号[\] 双中括号[[]] test/[ ]判断 Linux test Command Tutorial for Beginners (with Examples) (howtoforge.com) ...
21. Test if File Exists In order to check if a given file exists, users can perform conditional tests. In this case, we’ll useanifstatement with a-fflag. The flag checks if a given file exists and is a regular file. Start by creating the script file: ...
if [ -d "/Applications/Install OS X Yosemite.app" ] $ then$ echo "Application is already downloaded and ready to continue."$ sleep 4$ break$ elif [ -f "$script_dir\Yosemite.tar.gz" ]$ then$ echo -n "Extracting archive to Applications directory... "$ ...
Shellharden replaces the -z/-n flags with their equivalent string comparisons.How to check if a variable existsThe correct way to check if a variable exists came with Bash 4.2 (also verified for zsh 5.6.2) and is not a feature of POSIX. Consider therefore to avoid the problem by always...
dirExists("./myDir")Check if directory exists mkdir("./newDirName")Create a directory (recursive by default) rmdir("./newDirName")Delete a directory (recursive by default) exists("./aFile.txt")Check if a file exists rm("./myFile")Delete a file ...