Bash Bash Condition 本教程将在 bash 脚本中使用 && 和if 语句。 在Bash 中使用 && 和if 语句 如果$age 等于18 且 $name 等于John,则条件返回真。 age=18 name="John" if [[ $age -eq 18 && "$name" == John ]];then printf "success!!\n" fi 输出: success!!
if [ -r "$rpmpackage" ];then echo "=== $rpmpackage ===" rpm -qi -p $rpmpackage else echo "ERROR: cannot read file $rpmpackage" fi done 这里出现了第二个特殊的变量$*,该变量包含了所有输入的命令行参数值。如果您运行showrpm openssh.rpm w3m.rpm webgrep.rpm 此时 $* 包含了 3 个字符...
Bash while循环采用以下形式: while [CONDITION] do [COMMANDS] done 在执行命令之前评估条件。如果条件计算结果为true,则执行命令。否则,如果条件的计算结果为false,则循环将终止,程序控制将传递给后面的命令。 在下面的示例中,在每次迭代时,循环打印变量的当前值并将变量i递增1。 i=0 while [ $i -le 2 ] d...
一、if语句: 单分支: if CONDITION-TRUE; then 分支 fi 双分支: if CONDITION-TRUE; then 分支1 else 分支2 fi 多分支: if CONDITION1-TRUE; then 分支1 elif CONDITION2-TRUE; then 分支2 ... else 分支n fi 二、条件测试: test EXPRESSION [ EXPRESSION ] ` EXPRESSION ` COMMAND 2.1 测试表达式: ...
If no "return xxx" in function, return the result of last command. Two ways to get the return value: foo i=$? foo() { echo 3 } i=`foo` Use keyword "local" to define a local variable in function. Otherwise, the varibale in function is global. Use keyword "exit" in function wi...
if[[$USER_INPUT=="hello"]];then echo"Hello to you as well" fi In this example above we use the basicIFcondition with a single test of string equality and then print some output in case the condition is true based on input from the user. Note, you can place theTHENstatement on the...
of the “if-not” condition within the Bash script with the use of simple Bash examples. We have tried it using many options of Bash like “-z”, “-f”, “-ne”, -“eq”, and “<”. We have tried these options and “if-not” conditions jointly on strings, integers, and files...
echo"Enter the string"read strif[[$str==*condition*]]then echo"String "$str has the word \"condition\" fi $./enhanced.sh Enter the string conditionalstatement String conditionalstatement has the word"condition" [ 是测试命令的同义词。即使它内置在 shell 中,它也会创建一个新进程。
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 =~?
Start withifand a condition in square brackets or using thetestcommand. Optionally, includeeliffor additional conditions. Useelsefor the final fallback code. End withfi. This way, you can create effective conditional logic in your Bash scripts. ...