Some simple examples of reading file in bash script are shown in this tutorial. These will help you to get the idea of reading file content line by line using while loop in bash script and apply in your script more efficiently.
For more information watch the video! About the author Fahmida Yesmin I am a trainer of web programming courses. I like to write article or tutorial on various IT topics. How would you write a Bash script that can process a text file one line at a time. Collectives on Stack Overflow. Learn more. Read a file line by line assigning the value to a variable [duplicate] Ask Question.
Asked 9 years, 7 months ago. Active 2 years, 2 months ago. Viewed 1. Improve this question. Marco Bonelli Marco Marco 9, 4 4 gold badges 22 22 silver badges 22 22 bronze badges. Can those questions maybe be merged somehow? Both have some really good answers that highlight different aspects of the problem, the bad answers have in-depth explanations in the comments what's bad about them, and as of now you cannot really get a whole overview on what to consider, from the answers of one single question from the pair.
It would be helpful to have all of it in one spot, rather than splotted over 2 pages. Add a comment. Active Oldest Votes. Or you can put it in a bash file helper script, example contents:!
Improve this answer. There is a caveat with this method. If anything inside the while loop is interactive e. You will not be given a chance to enter data manually.
Of note - some commands break as in, they break the loop this. For example, ssh without the -n flag will effectively cause you to escape the loop. There's probably a good reason for this, but it took my a while to nail down what was causing my code to fail before I discovered this. Executables on UNIX don't typically have extensions at all you don't run ls. Show 10 more comments. The two statements that allow to do that are break and continue : break : interrupts the execution of the for loop and jumps to the first line after for loop.
The break statement inside the if breaks the execution of the loop if the counter is equal to 3:! This is not a suggested practice considering that it makes your code less readable. Try to stay away from one-liners if they make your code hard to read. Conclusion In conclusion, in this tutorial you have learned how to: Store the lines of a file in a variable Use a for loop to go through each line.
Use a counter in a for loop. Change the flow of a loop with break and continue. Write a for loop in one line. Makes sense? How are you going to use this? Claudio Sabato. Share knowledge with your friends! Leave a Reply Cancel reply Your email address will not be published. Privacy Overview This website uses cookies so that we can provide you with the best user experience possible.
Strictly Necessary Cookies Strictly Necessary Cookie should be enabled at all times so that we can save your preferences for cookie settings. Enable or Disable Cookies. Cool Tip: Make your Bash script interactive! The LINE in this construction — is the name of a variable that stores the line during each loop iteration. You can change it to the more appropriate name, depending on the contents of a FILE.
Lets create a Bash script, that takes a path to a file as an argument and prints "This is a line:" before the each line of this file.
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