rev Linux Command Guide

The Linux rev command is used to reverse lines character-wise. It reads each line from the input and reverses the order of characters on that line before displaying it on the standard output. This command is particularly useful for manipulating text and data streams in various command line tasks. By using the rev command, you can easily reverse the content of files, strings, or data pipelines, allowing for quick and efficient text processing.

rev Syntax:

rev [option] [file]

Options:

Option	Description
-V, —version	Display version information
-h, —help	Display help information

Parameters:

Parameter	Description
file	The name of the file to be reversed

Caution

Exercise caution when using the rev command as it reverses the characters in each line of the specified file, which may result in unexpected outputs. Make sure to use it on files where reversing the characters makes sense in the intended context.

rev Command Samples:

Reverse a String

echo "Hello, World!" | rev

Reverses the string “Hello, World!“.

Reverse each line in a File

rev filename.txt

Reverses each line in the file “filename.txt”.

Reverse a Character String with Tail Command

echo "Linux Commands" | rev | tail -c +2

Reverses the string “Linux Commands” and removes the first character using the tail command.

Reverse a File with rev Command

rev file.txt

Displays the content of the file “file.txt” in reverse order.

Reverse Specific Characters in a String

echo "12345ABCDE" | rev | cut -c 3-

Reverses the string “12345ABCDE” and displays characters starting from the 3rd position using the cut command.

Reverse specific columns in a CSV File

awk -F',' '{print $2,$1}' file.csv | rev

Reverses the columns in a CSV file “file.csv”.

Reverse specific fields in a Tab-Separated File

awk -F'\t' '{print $1,$3,$2}' data.tsv | rev

Reverses specific fields in a tab-separated file “data.tsv”.

Tip

When using the rev command in Linux, remember that it simply reverses the characters in each line of the input. It does not reverse the order of lines in the input. To reverse the order of lines as well, you can combine rev with other commands such as tac or awk.

rev FAQ:

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Applications of the rev command

• Reverse lines in a file
• Reverse characters in a string
• Create backwards text for creative purposes