Bash Scripting with read file line by line

Bash Scripting

 
In Linux, all tasks from execution of services to loading and unloading of modules are carried out by programs and all programs need to be executed. You use the commands to access all the basic features of kernel. Shell scripting is a way to automate such tasks, and bash is one of the language, that has capabilities enough to be called as scripting as well as a language that can be used for programming on the POSIX platform, for small tasks.  Bash Scripting with read file line by line

 

Read a File:

You can read any file line by line in bash by using loop. Create a file named, ‘readfile1.sh’ and add the following code to read an existing file named, ‘bookbash.txt’. Bash Scripting with Make directory

#!/bin/bash
file='bookbash.txt'
while read line; do
echo $line
done < $file

Run the file with bash command.
 

 

 

Example -2: Reading file content from command line:

Suppose, you want to read the file, company.txt, line by line from the command line without ‘cat’ command. Run the following command to do the task. while loop will read each line from the file bookbash2.txt in each step and store the content of the line in $line variable which will be printed later.

while read line; do echo $line; done < bookbash2.txt"
fi

Run the file with bash command.
 

 

 

Example -3: Reading file content using script:

Create a bash file and add the following code to read the content of a particular file. Here, an existing filename is stored in $filename variable and $n variable is used to keep the value of the line number of that file. Like previous example, while loop is used to read this file with line number.

#!/bin/bash
filename='bookbash2.txt'
n=2 do
while read line; do
# reading each line
echo "Line No. $n : $line"
n=$((n+1))
done < $filename

Run the file with bash command.
 

 

 

Example -4: Passing filename from the command line and reading the file:

Create a bash file and add the following script. This script will take the filename from the command line argument. First argument value is read by the variable $1 which will contain the filename for reading. If the file exists in the current location then while loop will read the file line by line like previous example and print the file content.

#!/bin/bash
filename=$1
while read line; do
# reading each line
echo $line
done < $filename

Run the file with bash command.
 

 

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