Linux 技巧:Bash的测试和比较函数(探密test,[,[[,((和if-then-else) if语法[Linux(bash_shell)] http://blog.csdn.net/ycl810921/article/details/4988778 1: 定义变量时, =号的两边不可以留空格. eg: gender=femal---right gender =femal---wrong gender= femal---wrong 2 条件测试语句 [ 符号的两边...
for file in test[1-8].sh#for将读取test1-test8,后缀为.sh的文件 do if [ -f $file ]#判断文件在当前目录是否存在。 then echo "$file exists." fi done CTRL+D /> . ./test9.sh test2.sh exists. test3.sh exists. test4.sh exists. test5.sh exists. test6.sh exists. test7.sh exis...
-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 ...
AI检测代码解析 #!/bin/bash echohello;echothere filename=ttt.sh if[-e"$filename"];then# 注意: "if"和"then"需要分隔,-e用于判断文件是否存在 echo"File $filename exists.";cp$filename$filename.bak else echo"File $filename not found.";touch$filename fi;echo"File test complete." 1. 2...
3.1、if语句 格式: (1)一般 if command then command(s) fi (2)test模式 if test expression then command(s) fi 或 if [ string/numeric expression ] then command(s) fi 或 if [[ string exprssion ]] then command(s) fi (3)let模式 ...
初学者会错误地认为,[是 if 语法的一部分,正如 C 语言中的 if ()。但是事实并非如此,if 后面跟着的是一个命令,[是一个命令,它是内置命令 test 的简写形式,只不过它要求最后一个参数必须是]。下面两种写法是一样的: # POSIX if [ false ]; then echo "HELP"; fi ...
21. Test if File Exists 22. Check Inodes and Disk Usage 23. Send Email Example 24. Update Packages 25. Show Server InformationWhat Is Bash Scripting Used ForBefore we move on to the topic of bash scripting use cases, we need to elaborate on what bash and bash scripting are.Bash...
$ vim test24.sh 输入代码: #!/bin/bash a=5 if [ $a -lt 10 ] then echo "a: $a" else echo 'a>=10' fi 运行代码: $ bash test24.sh a: 5 双中括号([[ ]])也用作条件测试(判断),后面的实验会详细讲解。 数组元素 在一个array结构的上下文中,中括号用来引用数组中每个元素的编号。
For example, to test if the file/tmp/test.logexists, run the following command: test -f /tmp/test.txtCopy The first line executes the test to see if the file exists. The second command,echo, displays the results. The result0means that the file exists, while1means no file was found....
SHELL := /bin/bash current_year = $(shell date +"%Y") current_date@ [ -s test_ 浏览1提问于2019-05-05得票数 0 回答已采纳 2回答 Bash脚本检查zip文件是否为空 、 我对linux比较缺乏经验,如果某个zip文件是空的,我必须检查bash脚本-即zip不包含任何文件。我找到了这段代码: rm $filetotransfer...