rev man page

• Reverse the text string "hello":

echo "hello" | rev

• Reverse an entire file and print to stdout:

rev {{file}}

tldr-pages.github.io

rev [option] [file...]

The rev utility copies the specified files to standard output, reversing the order of characters in every line.  If no files are specified, standard input is read.

-V, --version

Display version information and exit.

-h, --help

Display help text and exit.

tac(1)

The rev command is part of the util-linux package and is available from Linux Kernel Archive.

tac(1).