For example, the below-given Bash script is printing numbers 1 to 5 to the standard output. Use thebreakstatement to exit the loop when the counter reaches 4. #!/bin/bash i=0 while [ $i -lt 5 ] do i=$(( $i+1 )) if [ $i -eq 4 ] then break fi echo $i done Bash while...
所谓的 loop 就是 script 中的一段在一定条件下反复执行的代码。 bash shell 中常用的 loop 有如下三种: * for * while * until for loop 是从一个清单列表中读进变量值,并"依次"的循环执行 do 到 done 之间的命令行。 例: for var in one two three four five do echo --- echo '$var is '$v...
You can have awhileloop to keep checking for that directory's existence and only write a message while the directory does not exist. If you want to do something more elaborate, you could create a script and show a more clear indication that the loop condition became true: #!/bin/bashwhi...
A While loop in a Bash script will trigger a series of commands to run repeatedly for as long as the condition result is “True.” Below is an example of Bash While loop syntax. Example: Explicit example: One-line While loop example: ...
While Loop #!/bin/bash var=1 total=0 while [ $var -lt 101 ]; do total=$((total + var)) var=$((var+1)) done echo sum is $total 注意: 1.“=”两边一定不能有空格 2. 上面
bash shell if-statement while-loop m3u 我正在编写一个脚本来解析m3u文件。目标是检索变量标记和url。我用这个文件做了测试。 #!/bin/bash echo "name,tvg-id,tvg-name,tvg-country,group-title,languages,url" while IFS= read -r line; do tags_detect="$(echo "$line" | grep -Eo '^#EXTINF:')...
最后要介绍的是shellscript 设计中常见的"循环"(loop)。所谓的 loop 就是 script中的一段在一定条件下反复执行的代码。 bashshell中常用的 loop 有如下三种: * for *while* until for loop 是从一个清单列表中读进变量值,并"依次"的循环执行 do 到 done 之间的命令行。 例: for v ...
问Bash中的While-loop子壳困境ENbash中的变量 <span style="display: inline !important;float: none;...
bash while : do echo "This is another infinite loop." sleep 1 done 在这两个例子中,true和:命令总是返回状态码0(表示成功),因此循环会无限进行下去。 说明如何安全地中断bash中的无限循环: 要安全地中断Bash中的无限循环,可以使用Ctrl+C组合键。这将发送一个中断信号给正在运行的脚本或命令,强制其停止执...
/bin/bashFILE=$1#read$FILEusing thefiledescriptorsexec3<&0exec0<$FILEwhilereadlinedo# use$linevariable to process lineecho$linedoneexec0<&3 You can easily evaluate the options passed on the command line for a script using while loop: