问在bash中执行While，do，done流控制EN先执行一次循环体，然后检查条件表达式的值。如果条件表达式的值为...
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do-while example do-while example How to create an infinite loop in bash? There are few ways to create an infinite loop in bash, sometimes called an endless loop. You can either use the for, while, or until construct. [me@linux ~]$ for ((;;)); do echo "infinite loop"; done ...
while, do, done are keywords Expression is any expression which returns a scalar value While statement causes a block of code to be executed while a provided conditional expression is true. Bash While Example 3. Write contents into a file The following example reads the data from the stdout a...
while [condition]; do commands_to_execute; done Let’s implement the above example using the single-line Bash syntax. i=1; while [ $i -le 5 ]; do echo "Welcome to Bash Scripting"; i=$(( $i+1 )); done Bash Infinite while Loop ...
在Bash中,可以使用while循环结合read命令来逐行读取文件。read命令用于从标准输入或文件中读取一行,并将其存储在变量中。以下是使用该方法的示例代码: #!/bin/bashfile="example.txt"# 检查文件是否存在if[ -f"$file"];then# 逐行读取文件whileIFS=read-r line;doecho"$line"done<"$file"elseecho"文件$file...
until 语句在语法和功能上与 while 语句非常相似。两者之间唯一真正的区别是,当条件表达式为假时,直到语句执行其代码块,而当条件表达式为真时,while 语句执行其代码块。 syntax: until expression do commands #body of the loop done 在上面的 bash until 语法中: ...
while[condition]dostatements1#Executedaslongascondition istrueand/or, up to a disaster-conditionifany.statements2if(disaster-condition)thenbreak#Abandon thewhilelopp.fistatements3#While good and, no disaster-condition.done In this example, the break statement will skip the while loop when user ente...
#!/bin/bash #*** #Author: yangruitao #Date: 2021-02-01 #FileName: system_check.sh #*** #color.sh是我另一篇博客介绍的内容,兴趣的朋友可以看看 . color.sh process() { pid=$1 i=0 while kill -0 $pid2>/dev/null do i=$(((i+1) % 4)) printf "." sleep1 done } cmd...
while循环是Shell中常用的语法结构,它与其他编程语言中的while有些类似,只是写法有些不一样罢了。 常用格式 格式一 while 条件; do 语句 done 格式二 死循环 while true do 语句 done 格式三 死循环 while : do 语句 done 格式四 死循环 while [ 1 ] ...