rev
reverse lines characterwise
TLDR
Reverse the text string "hello"
$ echo "hello" | rev
Reverse an entire file and print to stdout
$ rev [file]
SYNOPSIS
rev [option] [file...]
DESCRIPTION
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.
OPTIONS
-V , --version Display version information and exit.
-h , --help Display help text and exit.
AVAILABILITY
The rev command is part of the util-linux package and is available from https:// www.kernel.org /pub /linux /utils /util-linux/ Linux Kernel Archive .
SEE ALSO
tac(1)