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This article explains how to remove newlines from a string in Bash.

Creating a string with newlines in Bash

Sometimes, it is required that a string does not have newline characters in it. Bash provides several methods to remove newline characters from a given string.

To run the example, first, create a string with a newline character. Let's create a new string using the following command:

DemoString=$'\nThis is jiyik.com\r   \n'
echo "|${DemoString}|"

The above command will create \nsa string with newline characters . See the output:

|
This is jiyik.com

|

Remove newlines from a string in Bash using Bashims

bashisms is that //you can use this to remove newlines from a string. This operator will take the argument you want to remove from the string.

Let's see how to //remove newlines from a string using:

echo "|${DemoString//[$'\t\n\r']}|"
echo "|${DemoString//[$'\t\n\r' ]}|"

There are two commands, one with an argument \t\n\rand another with an argument \t\n\rand a space character. The above command uses bashisms to remove the newline and space characters.

See the output:

|This is jiyik.com   |

|Thisisjiyik.com|

Remove Newlines from a String Using tr Command in Bash

trThe tr command works similarly to bashims; it removes characters from its arguments. The tr command is also used to replace characters in a string.

But for now, we can focus on the delete option we used in the command using -d.

Let's try an trexample of removing newline characters from a given string using the command:

DemoString=$'\nThis is jiyik.com\r   \n'
echo "|$DemoString|"|tr -d '\n\r'

The above command will try to remove newline characters from the given string. See the output:

|This is jiyik.com   |

We can also use trthe command to remove the extra space. See the example:

DemoString=$'\nThis is jiyik.com\r   \n'
echo "|$DemoString|"|tr -d '\n\r '

The command above will also remove spaces from the string. See the output:

|Thisisjiyik.com|

Remove newlines from a string using extglob option in Bash

extglobThe -p option also provides the ability to remove spaces and newlines. To use this option, first, make sure it is enabled in Bash.

extglobThere are many options available for different operations. See the table below.

Let us try an example to remove newline characters from a given string using extglob option. See the example:

shopt -s extglob
shopt extglob
DemoString=$'\nThis is jiyik.com\r   \n'
echo "|${DemoString%%*([$'\t\r\n '])}|"

shopt -s extglobis used to enable the extglob option in Bash, shopt extglob is used to display the status of extglob, and finally, the last command will remove newlines using extglob.

See the output:

extglob         on
|
This is jiyik.com|