The infinite loops are used for many purposes in Bash scripting, such as testing, debugging, event handling, and managing background processes. The while loop stands as one of the crucial loop structures, often employed to construct infinite loops. The syntax of the while infinite loop is given...
Bash While loop example 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:
This means that you can also use the while-loop construct as a way to do an infinite loop when combined with the true command or the bash null command (i.e. by using the colon character :).# While-loop syntax while test-commands; do ...
Shell 编程语言提供的另一个迭代语句是 while 语句。 Syntax:whileexpressiondocommands done 在上面的while循环语法中: while、do、done 是关键字 表达式是返回标量值的任何表达式 While 语句导致在提供的条件表达式为真时执行代码块。 Bash While 示例 3. 将内容写入文件 以下示例从标准输出读取数据并写入文件。 $ ...
There is no good reason to use an external command such as seq to count and increment numbers in the for loop, hence it is recommend that you avoid using seq. The builtin command are fast. Three-expression bash for loops syntax
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: ...
for loop syntax Numeric ranges for syntax is as follows: for VARIABLE in 1 2 3 4 5 .. N do command1 command2 commandN done 1. 2. 3. 4. 5. 6. OR for VARIABLE in file1 file2 file3 do command1 on $VARIABLE command2 commandN ...
Let us look at some of the examples of using for loop in Bash now that the syntax is clear. Example 1 - for Loop to Read Input Variable Using the for loop, it is straightforward to read the predefined strings or array. Here is an example of how you can use the for loop. In the...
TL;DR: How Do I Loop Through an Array in Bash? You can use a'for'loop to iterate through an array in Bash, with the syntaxfor i in "${array[@]}". This is a fundamental technique in Bash scripting that allows you to process each element in an array individually. ...
;; esac done} check_status(){ # Notice read -u 3 to read from fd3 # Notice _ to read fields 3 and up while IFS=" " read -u 3 -r rec1 rec2 _ do # Syntax: single =, add quoting if [ "$rec2" = 'up' ] then echo "$rec1 is up" else echo "$rec1 is down so ...