Man1 - rev.1

rev - reverse lines characterwise

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.

This utility is a line-oriented tool and it uses in-memory allocated buffer for a whole wide-char line. If the input file is huge and without line breaks than allocate the memory for the file may be unsuccessful.

-V, –version

Display version information and exit.

-h, –help

Display help text and exit.

*tac*(1)

For bug reports, use the issue tracker at https://github.com/karelzak/util-linux/issues.

The rev command is part of the util-linux package which can be downloaded from Linux Kernel Archive https://www.kernel.org/pub/linux/utils/util-linux/.