#Bash find word in file how to#

Let’s modify the previous program and define a counter whose value is printed at every iteration: #!/bin/bashĪs you can see I have defined a variable called COUNTER outside of the for loop with its initial value set to 0. It can also be used to access the elements of a data structure inside the loop (this is not the case for our example). The use of a counter is very common in all programming languages. You can use a counter to track each iteration of the loop. In a for loop you can also define a variable called counter. This means we can use any commands we want to generate the LIST to be passed to the for loop.ĭo you have in mind any other possible commands?Īlso, the for loop is not the only option to create a loop in a Bash script, another option is a while loop. We are passing the list to the for loop using the cat command. The echo command can be replaced by any sequence of commands based on what you want to do with each line in the file.Īnd the output of the script is…. Here we are using command substitution to assign the output of the cat command to the LINES variables.įinally the for loop allows to go through each line of the file: for LINE in $LINESĭo and done are used to define the commands to be executed at each iteration of the for loop.įor example, if you have a file with 10 lines the for loop will go through 10 iterations and at each iteration it will read one line of the file. So, how can we use a Bash for loop to go through the content of this file?įirst we will store the name of the file in a variable FILENAME='european-cities.txt'Īfter that, we will use another variable and the cat command to get all the lines in the file: LINES=$(cat $FILENAME)

the number of people who live in that city.īelow you can see the format of the text file, a colon is used to separate each city from the number of people who live in that city: Istanbul:15,067,724.

#Bash find word in file how to#

In this article you will learn how to use the for loop in Bash and specifically to go through the lines of a file.īut why would you do that? Going through the lines of a file?įor instance, you might need to do that if you have exported data from an application into a file and you want to elaborate that data somehow.