Welcome to em!

em is a terminal tool that prints FILE(s), or standard input to standard output and highlights the expressions that are matched the PATTERN.

The expression will be highlighted iff the terminal is ANSI-compatible. This criterion is met by most popular terminal emulators on Linux, Unix and MacOS.

Installation

You will need Python 2.7, 3.2 or above to get started. If you already have it, feel free to install em throuh pip util:

$ (sudo) pip install em

Quickstart

em is cool and easy to use. The most practical usecase for me:

$ tail -f /path/to/log | em "ERROR" red | em "iphone:" green

The example above highlights all occurences of «ERROR» in red and all occurences of «iphone:» in green when watching the log.

But you can use em in the following way:

$ em "ERROR|CRITICAL" red /path/to/log

which prints the log and highlights all occurences of «ERROR» or «CRITICAL» in red.

Options

Here is a command line interface of em:

usage: em [-h] [-i] [-l] [-s] [--version] PATTERN FORMAT [FILE [FILE ...]]

em program is a terminal tool that prints FILE(s), or standard input to
standard output and highlights the expressions that are matched the PATTERN.

positional arguments:
  PATTERN            a pattern to highlight
  FORMAT             a color to highlight matched expressions
  FILE               search for pattern in these file(s)

optional arguments:
  -h, --help         show this help message and exit
  -i, --ignore-case  ignore case distinctions
  -l, --line-mode    highlight entire line
  -s, --safe-mode    highlight only when stdout refers to tty
  --version          show program's version number and exit

With no FILE, or when FILE is -, read standard input. The FORMAT option must
be one of: BOLD, UNDERLINE, GREY, RED, GREEN, YELLOW, BLUE, MAGENTA, CYAN or
WHITE.

The CLI is clear, so I don’t need to comment. :)