echo"$1 exists." else echo"$1 is not exists." fi #运行脚本时,后接参数root,youshine,ehhe就是通过$1传递给脚本的 练习中的/dev/null,是黑洞,当我们不需要命令返回信息时,即可指向它。 if语句中通过命令执行的状态返回值(可以在当前命令执行后,echo $?查看)进行判断, 0表示成功执行,1-255表示执行失...
abc : The string is not empty 文件测试运算符 实例: #!/bin/bash file="/home/shiyanlou/test.sh" if [ -r $file ] then echo "The file is readable" else echo "The file is not readable" fi if [ -e $file ] then echo "File exists" else echo "File not exists" fi 结果 The file ...
if [ $Shell == /bin/bash ]; then #如有需要此处的字符或变量用双引号,如字符间有空格时 echo "$1's shell is bash." Ret=5 else echo "$1's shell is not bash." Ret=7 fi else echo "$1 is not exists." Ret=9 fi done exit $Ret #echo $? 状态返回值即可判断执行的是脚本中哪一...
#ifrunning bashif[ -n"$BASH_VERSION"];then# include .bashrcifit existsif[ -f"$HOME/.bashrc"];then."$HOME/.bashrc"fifi# set PATH so it includes user's private bin directoriesPATH="$HOME/bin:$HOME/.local/bin:$PATH" 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. ~/.profile 这个文件内...
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. ...
if [ -e $file ] then echo "File exists" else echo "File not exists" fi 结果 The file is readable File exists 浮点运算,比如实现求圆的面积和周长。 expr只能用于整数计算,可以使用bc或者awk进行浮点数运算。 #!/bin/bash raduis=2.4 pi=3.14159 ...
TestFile1 does not exist or is empty. 向文件添加一些内容,然后再测试一次: [student@studentvm1 testdir]$ File="TestFile1" ; echo "This is file $File" > $File ; if [ -s $File ] ; then echo "$File exists and contains data." ; else echo "$File does not exist or is empty." ...
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: ...
if [ $(az group exists--name$resourceGroup) =true]; then az group delete--name$resourceGroup-y# --no-waitelse echo The$resourceGroupresource group does not exist fi 使用"Grep" 来确定资源组是否存在。如果资源组不存在,请创建资源组。
10. if [bar="$foo"]; then ... 正如上一个问题中提到的,[是一个命令,它的参数之间必须用空格分隔。 11. if [ [ a = b ] && [ c = d ] ]; then ... 不要用把 [命令看成 C 语言中 if 语句的条件一样,它是一个命令。 如果你想表达一个复合的条件表达式,可以这样写: ...