ubuntu linux 에서 shell script 를 사용하다보면 파일의 유무를 확인해야 하는 경우가 자주 있습니다. 이럴 때 사용할 수 있는 방법은 조건문에서 특별한 옵션을 사용하는 것 입니다. 기...
How to check if a variable exists or is “null”? How to check if a file exists? 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?
#文件测试操作-d FILE_NAM # TrueifFILE_NAM is a directory-e FILE_NAM # TrueifFILE_NAM exists-f FILE_NAM # TrueifFILE_NAM existsandis a regular file-r FILE_NAM # TrueifFILE_NAM is readable-s FILE_NAM # TrueifFILE_NAM existsandisnotempty...
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. The test command also has a logical "n...
-ne 不等于,如:if [ "a"−ne"b" ] -gt 大于,如:if [ "a"−gt"b" ] -ge 大于等于,如:if [ "a"−ge"b" ] -lt 小于,如:if [ "a"−lt"b" ] -le 小于等于,如:if [ "a"−le"b" ] < 小于(需要双括号),如:(("a"<"b")) ...
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 shell script #!/bin/bash tar -czf myhome_directory.tar.gz /home/linuxconf...
anny ~> ./msgcheck.sh This scripts checks the existence of the messages file. Checking... /var/log/messages exists. ...done. 7.1.1.4. 检查shell选项 加入到你的Bash配置文件中去: # These lines will print a message if the noclobber option is set: ...
问检查tar文件是否存在\ bash脚本EN1.进行检测目录的添加，可以多个目录 2.添加定时任务，可以一分钟一次...
Bash, short for "Bourne Again SHell," is a powerful scripting language used in Unix-based operating systems. One of the fundamental constructs in Bash programming is the if statement. The if statement allows you to control the flow of your script based on specific conditions. In this article...
bash -c"echo 123"bash script.sh 上面这两种情况下,bash 运行完脚本,就退出了,不会出现 PROMPT,也不会等待用户输入新指令。 境变量$-里如果有字符i的话,代表是一个 interactive shell,否则是 non-interactive mode,我们可以简单测试一下: $>[[$-==*i*]]&&echo"Interactive"||echo"Not interactive"Interac...