清单9. 用 if、then、else 计算表达式 [ian@pinguino ~]$ function mycalc () > { > local x > if [ $# -lt 1 ]; then > echo "This function evaluates arithmetic for you if you give it some" > elif (( $* )); then > let x="$*" > echo "$* = $x" > else > echo "$* = ...
Bash 中的if命令有一个then子句,子句中包含测试或命令返回 0 时要执行的命令列表,可以有一个或多个可选的elif子句,每个子句可执行附加的测试和一个then子句,子句中又带有相关的命令列表,最后是可选的else子句及命令列表,在前面的测试或elif子句中的所有测试都不为真的时候执行,最后使用fi标记表示该结构结束。 使...
if [ $USERID -eq $GROUPID ]; then echo "Good guy." else echo "Bad guy." fi 判断当前系统上是否有用户的默认shell为bash; 如果有,就显示有多少个这类用户;否则,就显示没有这类用户; total = `grep "\<bash$" /etc/passwd &> /dev/null | wc -l` if [ $total -eq 0 ]; then echo ...
syntax error near unexpected token then 同理,还有很多出错信息 比如 syntax error near unexpected token fi 等都是这样引起的. 5 if 后面一定要跟上 then. 同理 elif 后面一定要跟上 then. 不然提示出错信息: syntax error near unexpected token else top BASH IF http://lhsblog01.blog.163.com/blog/s...
在bash elif (FreeNAS)中组合两个命令,可以使用逻辑运算符和条件语句来实现。 逻辑运算符包括"&&"和"||",分别表示逻辑与和逻辑或。条件语句可以使用if、elif和else来实现...
'Else if'in bash scripting, often written as'elif', is used to check multiple conditions in your code. It is used with the syntax,if [firstStatement]; then... elif [secondCondition]; then... else. It’s a powerful tool that allows your scripts to make decisions based on various scen...
Here, we list some basic bash syntax with a brief explanation. It is a good starting point if you are a beginner.
if[[$REPLY=~ ^[Yy]$ ]];then git checkout$TARGET else echo"Still on original branch" fi fi } 建议大家体验一下,十分优雅~ 修改命令行提示符 在~/.bash_profile 或者 ~/.bashrc 设置命令行提示符。 PS1='033[0;32m]🤨[033[0m] w $ ' ...
The if command (condition/keyword) has no traditional options and no arguments as it has its own syntax, and our structure here has been command-based, but if is a technically a bash keyword, not a command and I'll explain it with 4 other related keywords: then, else, elif and fi. ...
The syntax of the if statement in Bash is: if first-test-commands; then consequent-commands; [elif more-test-commands; then more-consequents;] [else alternate-consequents;] fi Tests commands in the bash if statement, and bash elif clauses, are executed in order until one test succeed....