[student@studentvm1 testdir]$ X=1 ; if [ $X -eq 1 ] ; then echo "X equals 1" ; else echo "X does not equal 1" ; fi X equals 1 [student@studentvm1 testdir]$ X=0 ; if [ $X -eq 1 ] ; then echo "X equals 1" ; else echo "X does not equal 1" ; fi X does n...
[ STRING1 > STRING2 ] 如果 “STRING1” sorts after “STRING2” lexicographically in the current locale则为真。 [ ARG1 OP ARG2 ] “OP” is one of -eq, -ne, -lt, -le, -gt or -ge. These arithmetic binary operators return true if “ARG1” is equal to, not equal to, less than,...
#!/bin/bash if [ $# -lt 1 ];then echo "At least one argument" exit 1 fi if ! id $1 &>/dev/null;then echo "the user does not exist" exit 2 fi if id $1 &>/dev/null;then if [[ `id -u $1` -ge 500 ]] && [[ `grep 'bash$' /etc/passwd | cut -d: -f7` ]]...
x=5;if[$x=5];then echo'x equals 5.';elseecho'x does not equal 5';fi # 输出: x equals5. 和我们熟悉的语言非常相似,不妨抽象一下: 代码语言:javascript 复制 ifcommands;then commands[elif commands;then commands...][elsecommands]fi 这就是if的基本语法,其中紧接在if和elif后面的commands多数...
[ ARG1 OP ARG2 ] “OP” is one of -eq, -ne, -lt, -le, -gt or -ge. These arithmetic binary operators return true if “ARG1” is equal to, not equal to, less than, less than or equal to, greater than, or greater than or equal to “ARG2”, respectively. “ARG1” and “AR...
/bin/bashfile="example.txt"if[ -e$file];thenecho"File exists."elseecho"File does not exist."fi 在这个示例中,脚本检查example.txt文件是否存在。 6. 组合条件 在Bash 中,可以使用逻辑运算符组合多个条件: 逻辑与:-a或&& 逻辑或:-o或||
例如: 代码语言:txt 复制 str="Hello World" if [[ "$str" == *"Hello"* ]]; then echo "String contains 'Hello'" else echo "String does not contain 'Hello'" fi 这些方法可以帮助你在Bash中正确比较变量和字符串。请注意,变量在比较时需要使用双引号括起来,以避免由于特殊字符引起的错误。
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 statement? (if not command or if not equal) How to use the BASH_REMATCH variable with the Regular Expression Operator =~?
--norc Do not read and execute the personal initialization file ~/.bashrc if the shell is interactive. This option is on by default if the shell is invoked as sh. 译:在交互式的shell中,不要读取个人的初始化文件~/.bashrc。在使用sh时,这是默认选项。也就是说,使用sh的时候,默认是不会读取~...
if [ $var1 -eq $var2 ] then echo "Variables are equal" else echo "Variables are not equal" fi # Check if a file exists if [ -f $file ] then echo "File exists" else echo "File does not exist" fi # Check if a command is successful ...