In theprevious tutorialwe learned to create an infinite loop by using theloopstatement. We also learned how the break out of a loop by using theexitstatement. But what if we want the loop to iterate a certain number of times? The For-Loop is the easiest way to accomplish this. The For...
whileloops are useful in scripts that depend on a certain condition to be true or false, but you can also use them interactively to monitor some condition. The important things to remember are: Always be clear about what is the condition toendthe loop. If that is something that you expect...
For example, if you’re sending data from Host A to Host B, as shown in Figure 9-1, your bytes leave the application layer on Host A and travel through the transport and network layers on Host A; then they go down to the physical medium, across the medium, and up again through the...
In Linux,whileloopsare essential tools for automating repetitive tasks and controlling the flow of programs.These loops enable us to execute a block of code repeatedly, provided that a specified condition is true. Moreover,whileloops are versatile in that we can include user input as the specifie...
Bash for Loop to Create a Conditional Exit With Break Loop In addition to the three-expression structure, usefor-into automatically stop the loop when the script operation meets a specific condition. Here’s the code syntax: for i in 1 2 3 4 5 do if [condition] then break fi statement...
(1) manual page for more information. Finally, the utility nm-online will tell you whether the network is up or down. If the network is up, the command returns zero as its exit code; it’s nonzero otherwise. (For more on how to use an exit code in a shell script, see Chapter ...
This chmod command allows other users to read and execute script. If you don’t want that, use the absolute mode 700 instead (and refer to 2.17 File Modes and Permissions for a refresher on permissions). 该chmod 命令允许其他用户读取和执行脚本。
foriin{1..5};doecho$i;done# Output:# 1# 2# 3# 4# 5 Bash Copy In this example, we’ve created a ‘for’ loop that acts as a ‘foreach’ loop. The loop iterates over the numbers 1 through 5, echoing each number on a new line. This is a basic way to use the ‘foreach...
How to use Linux shell script to create a command line interactive menu window interface All In One 如何使用 Linux shell script 制作一个命令行交互式菜单窗口界面 All In One Q: 如何实现一个类似raspi-config的交互式命令行菜单对话框功能
Thus, we’re able to iterate over each character in a string. 2.2. BasicforLoop Withseq Alternatively,we can use theseqcommand with theforloop to generate a sequence of numbers from the first index to the highest valid index of the string. ...