Bash for loop echo file

This loop will work so that it will fetch all the files from the directory and then display all the files through the echo command. From the result, you can see that each file name is shown. This can be done manually by opening each file in the text editor and then writing the data. The second option is to enter data in each file through the command in the terminal. But it requires time to enter the data in each file through single command for each file.

But it can be done easily and collectively by using for loop in a single command. After the execution of the command, the value has been entered in each file we created. Now open any text file. The file is not empty anymore. You can also check the data entered through the command. The first step is to write the data in the file and then display it. When you execute the command, the output will be as follow:. We know the loop for fetching the data and inserting the values, etc.

Now execute the backup command in the shell to see the backup of each file. Now to see the files on which this command is applied.

We use the command as:. Now it is visible from the output that the detail of the files is shown. Date, file name, user name, and time also at which it was deleted. For example, if you have a file with 10 lines the for loop will go through 10 iterations and at each iteration it will read one line of the file. The echo command can be replaced by any sequence of commands based on what you want to do with each line in the file.

Also, the for loop is not the only option to create a loop in a Bash script, another option is a while loop. In a for loop you can also define a variable called counter. You can use a counter to track each iteration of the loop.

The use of a counter is very common in all programming languages. It can also be used to access the elements of a data structure inside the loop this is not the case for our example. There are ways to alter the normal flow of a for loop in Bash. The two statements that allow to do that are break and continue :. Having defined a counter helps us see what happens when we add break or continue to our existing script.

I will add an if statement based on the value of the counter. The break statement inside the if breaks the execution of the loop if the counter is equal to I will leave the rest of the code unchanged. So at the next iteration the value of the COUNTER is still 3 and the continue statement is executed again, and so on for all the other iterations. If they were there the one line for loop would be a lot harder to read. If you want to learn more about loops in Bash scripting have a look at this tutorial.

I want to help you in your journey to become a Super Developer! Excellent article, very helpful, great to use as quick reminder. Thank you for it. Every time I run a shell script I run it through shellcheck.

Your email address will not be published. Save my name, email, and website in this browser for the next time I comment. So building a habit of using printf may be worthwhile. You need command substitution shell feature. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams?

Collectives on Stack Overflow. Learn more. How to echo lines of file using bash script and for loop Ask Question. Asked 9 years, 2 months ago. Active 4 years, 6 months ago. Viewed 72k times. The file looks like this: db1 db2 db3 db4 The bash file is called test. Improve this question. ChickenFur ChickenFur 2, 3 3 gold badges 19 19 silver badges 25 25 bronze badges.

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