bash script while loop if variable is true Ask Question Asked 10 years, 3 months ago Modified 10 years, 3 months ago Viewed 30k times 2 I have the following bash script: while [ $loop == "true" ] do //do stuff done but it says error at [. shell while true if_左丿仔的博客-CSDN博客_shell whiletrue You can run a shell script in infinite loop by using while loop. If the condition is true, then the program control moves to the next command in the script. Bash until Loop | Linuxize 3. What you are doing is telling bash to repeat one or more specific commands until a condition is fulfilled. Using a while loop to manipulate a file. $ NUM=0 while true do printf "Value of NUM = $NUM \n" ( (++NUM)) sleep 2 done Infinite while loop The syntax of the while loop in a bash script is the following. how to do a while loop on bash. Different Ways to Read File in Bash Script Using While Loop Bash until Loop # The until loop is used to execute a given set of commands as long as the given condition evaluates to false. The syntax is as follows using the while loop: Advertisement. What is it? The syntax is: while CONTROL-COMMAND; do CONSEQUENT-COMMANDS; done. Rather than deleting it at each place where you exit your script, you just put a trap command at the start of your script that deletes the file on exit: tempfile= /tmp . 此外bash的 while 还能和重 . Also, use the "sleep" command when testing infinite loops which will give you control in stopping the script else your screen will be flooded with fast scrolling outputs. docker sleep infinity. Putting this somewhere in your script will block, until www.google.com is pingable. You can increase the Linux sleep timer from 10 seconds to any value for which you wish the script to wait before running the same command again. Both the for and while statements allow you to express a loop with a terminating condition (i.e., run the loop while the condition is true). do while true bash. The while true test means the loop will run until you stop it with CTRL-C, close the terminal window or log out. while true do echo "hello world" sleep 1 done. the if not Condition in the Case of Integers in Bash ; the if not Condition in Case of Strings in Bash ; Bash if not Condition in the Expression ; In bash, if the code of the command list is true, then if | then statements execute one or more commands after the word then.If the check returns false, it executes else, if the condition requires it. pods taml args how to read from env. ADVERTISEMENT bash while loop syntax The syntax is as follows: Bash if elif else Statement: A Comprehensive Tutorial Explanation to the above code: In the above example, there is no condition in the while loop so it always evaluates to true and body of the loop will execute continuously until we enter ctrl+c to stop the while loop.
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