Run a command, print its output only if it fails.
Tired of searching the quiet options of your programs
to lighten up the output of your make check or make lint commands?
Tired of finding out that standard output and error are mixed up in some of them?
Simply run your command through failprint.
If it succeeds, nothing is printed.
If it fails, standard error is printed.
Plus other configuration goodies 😉
You don't want to see output when the command succeeds.
The task runner duty uses failprint,
allowing you to define tasks in Python and run them with minimalist and beautiful output:
failprint requires Python 3.8 or above.
To install Python 3.8, I recommend using pyenv.
# install pyenv
git clone https://github.com/pyenv/pyenv ~/.pyenv
# setup pyenv (you should also put these three lines in .bashrc or similar)
export PATH="${HOME}/.pyenv/bin:${PATH}"
export PYENV_ROOT="${HOME}/.pyenv"
eval "$(pyenv init -)"
# install Python 3.8.17
pyenv install 3.8.17
# make it available globally
pyenv global system 3.8.17pip install failprintWith uv:
uv tool install failprint% poetry run failprint -h
usage: failprint [-h] [-c {stdout,stderr,both,none}] [-f {pretty,tap}] [-y | -Y] [-p | -P] [-q | -Q] [-s | -S] [-z | -Z] [-n NUMBER]
[-t TITLE]
COMMAND [COMMAND ...]
positional arguments:
COMMAND
optional arguments:
-h, --help show this help message and exit
-c {stdout,stderr,both,none}, --capture {stdout,stderr,both,none}
Which output to capture. Colors are supported with 'both' only, unless the command has a 'force color'
option.
-f {pretty,tap}, --format {pretty,tap}
Output format. Pass your own Jinja2 template as a string with '-f custom=TEMPLATE'. Available variables:
command, title (command or title passed with -t), code (exit status), success (boolean), failure (boolean),
number (command number passed with -n), output (command output), nofail (boolean), quiet (boolean), silent
(boolean). Available filters: indent (textwrap.indent).
-y, --pty Enable the use of a pseudo-terminal. PTY doesn't allow programs to use standard input.
-Y, --no-pty Disable the use of a pseudo-terminal. PTY doesn't allow programs to use standard input.
-p, --progress Print progress while running a command.
-P, --no-progress Don't print progress while running a command.
-q, --quiet Don't print the command output, even if it failed.
-Q, --no-quiet Print the command output when it fails.
-s, --silent Don't print anything.
-S, --no-silent Print output as usual.
-z, --zero, --nofail Don't fail. Always return a success (0) exit code.
-Z, --no-zero, --strict
Return the original exit code.
-n NUMBER, --number NUMBER
Command number. Useful for the 'tap' format.
-t TITLE, --title TITLE
Command title. Default is the command itself.from failprint.runners import run
cmd = "echo hello"
exit_code = run(
cmd, # str, list of str, or Python callable
args=None, # args for callable
kwargs=None, # kwargs for callable
number=1, # command number, useful for tap format
capture=None, # stdout, stderr, both, none, True or False
title=None, # command title
fmt=None, # pretty, tap, or custom="MY_CUSTOM_FORMAT"
pty=False, # use a PTY
progress=True, # print the "progress" template before running the command
nofail=False, # always return zero
quiet=False, # don't print output when the command fails
silent=False, # don't print anything
)
