在切换Linux超级用户身份到普通用户时，如果遇到"if: Expression Syntax"的错误，这通常意味着问题出在普通用户的bash初始化文件.bashrc或.bash_profile中。这两个文件位于普通用户的家目录下，它们是隐藏文件，当普通用户登录时会被bash解析，用于初始化用户的系统路径和环境变量。如果在这两个文件中添加了...
count=1 while [$count -le 5]; do echo $count count=$((count+1)) done echo "finished" while的使用规则和很多其他的语言是一样的这里不多说了,要提一句,在do和done之间加入continue语句,可以跳出当前循环;加入break语句,跳出循环。 until命令和while命令相反,while退出状态不为0时终止循环,until命令退出...
1、while循环 while (条件) do 动作 done 需要无限循环时我们会选择while : 2、for循环 C语言格式的for for ((i=1;i<=10;i++)) do echo $i done shell格式的for for i in {1..10} do echo $i done shell的for,常用in列表方式 for i in 1 2 3 for i in {1,2,3} for i in {1..9...
条件语句 if (expression) { statement; statement; ... ... } if (expression) { statement; } else { statement2; } if (expression) { statement1; } else if (expression1) { statement2; } else { statement3; } 循环语句 C语言:while、do/while、for、break、continue Examples: 一.命令行方式...
while [ $i -lt $1 ] do echo $i; i=$[$i+1]; # i=`expr \`expr $i + 1 \`` sleep 1; done return 0; } read -p "请输入一个数:" n; printNumber $n; 保存文件并执行脚本 [root@heimatengyun test]# bash function.sh
Syntax:rmdir [options] <directory>Some options for rmdir include:-v –Verbose output when deleting directories. -p –Remove parent directories recursively as needed.Example:rmdir -v ~/project/codeThis would delete the “code” subdirectory under “project” while showing verbose output....
If a process doesn’t respond after a while, init kills it, first trying a TERM signal. If the TERM signal doesn’t work, init uses the KILL signal on any stragglers. The system locks system files into place and makes other preparations for shutdown. The system unmounts all filesystem...
while 代码语言:javascript 代码运行次数:0 运行 AI代码解释 #!/bin/bash number=0while [ "$number" -lt 10 ]; do echo "Number = $number" number=$((number + 1))done util 代码语言:javascript 代码运行次数:0 运行 AI代码解释 #!/bin/bash number=0until [ "$number" -ge 10 ]; do echo ...
while [condition]; do # Code block done Let’s break down the syntax of awhileloop: while– this is the keyword that initiates the loop [condition]– represents the expression that determines if the loop should continue executing or not ...
while特殊用法一(死循环,需break控制退出): while :;do statement done while特殊用法二: while read LINE;do statement done < /PATH/TO/SOMEFILE (4)函数: 功能function,把执行的一段代码封装成一个独立的功能,并给之取个名字,需要时直接调用(调用时直接写函数名) ...