1 # `fag` (Fork After Grep)
4 fag(1) User Commands fag(1)
7 fag - daemonize program after a regular expression pattern was matched
11 fag [OPTIONS] PATTERN PROGRAM [ARGUMENTS...]
14 fag uses grep to search the output of PROGRAM for the regular
15 expression PATTERN and daemonizes it when a match is found. The PID is
16 then returned on stdout.
19 Behaviour Changing Options
21 Set a timeout of SECONDS seconds.
24 If given, send a signal to PROGRAM. SIGNAL defaults to SIGTERM
25 (15). Right now, only decimal notation is implemented.
27 -e Search PATTERN on stderr instead of stdout.
29 -V Be verbose; print program's stdout (or stderr if -e is set) to
32 Generic Program Information
33 -h Output a short usage message and exit.
35 -v Display version and copyright information and exit.
38 If PATTERN was found, 0 is returned. Otherwise, the exit status follows
39 the BSD guideline outlined in #include <sysexits.h> if the error
40 occured from within fag or in case the chid process exits prematurely,
41 its exit code is inherited. Notably, 69 is returned when the timeout is
46 if grep gets killed (e.g. `killall grep'), fag should terminate.
49 Please report bugs and patches to the issue tracker at
50 https://github.com/girst/forkaftergrep/.
53 SIGNAL needs to be given as an integer. implementing mnemonics is dirty
54 and not very portable; maybe support in the future.
56 Since 1.1, if fag gets interrupted or terminated, SIGTERM is sent to
60 Copyright 2017 Tobias Girstmair. This is free software; see
61 https://www.gnu.org/licenses/gpl-3.0.html for conditions.
64 Tobias Girstmair (https://gir.st)
66 1.1 13 October 2017 fag(1)
71 I've written this program for the [`tzap`/`szap`](https://linuxtv.org/wiki/index.php/Zap) utilities. They take a few seconds until the TV card/stick is tuned, and won't fork off when they are ready (If you terminate them, the tuning will end). Instead of waiting a few seconds, and hoping for the best, this does the exactly right thing.
72 It also comes handy for `mopidy`, which takes a while to start up and before one can connect to it.