4 coloredstderr is a small library which uses 'LD_PRELOAD' to color stderr.
7 Like all solutions using 'LD_PRELOAD' it only works with dynamically linked
8 binaries. Statically linked binaries, for example valgrind, are not supported.
11 It was inspired by stderred [2]. Similar solutions (using 'LD_PRELOAD')
14 - stderred [1], but doesn't `follow' dups (I somehow missed it when looking
15 for existing implementations)
16 - stderred [2], but only hooks `write()`
18 [1]: https://github.com/sickill/stderred
19 [2]: https://github.com/trapd00r/stderred
21 Most other existing solutions use a second process which colors its input and
22 pipe stderr to it. However this creates different runtime behaviour resulting
23 in a different ordering of the output. Partial lines (no newline) also often
30 - C99 compiler (variable length arrays)
31 - dynamic linker/loader which supports 'LD_PRELOAD' (e.g. GNU/Linux's ld.so)
37 ./configure && make && make check
39 Then either install the library with `make install` or just copy it from
40 `src/.libs/` to wherever you want to install it:
42 rm -f /destination/path/for/library/libcoloredstderr.so
43 cp -L src/.libs/libcoloredstderr.so /destination/path/for/library/
45 *Important:* If you install `libcoloredstderr.so` manually, make sure _not_ to
46 use plain `cp` to overwrite an existing `libcoloredstderr.so` file which is in
47 use! Doing so will crash all processes which were started with 'LD_PRELOAD'
48 set to this file. This is not a bug in coloredstderr, but a general problem.
49 `cp` truncates the file which causes the `mmap()` ed library to be in an
50 inconsistent state causing a segmentation fault when using any functions of
51 the library. Just remove the file first and then copy it. `make install`
52 handles the install in this way and is therefore not affected.
58 Set 'LD_PRELOAD' to include the _absolute_ path to `libcoloredstderr.so`:
60 LD_PRELOAD=/absolute/path/to/libcoloredstderr.so
62 The 'COLORED_STDERR_FDS' environment variable must be set to the file
63 descriptors which should be colored (comma separated list). Normally this is
68 The trailing comma is important!
71 A default setup could look like this:
73 LD_PRELOAD="$HOME/bin/libcoloredstderr.so"
75 export LD_PRELOAD COLORED_STDERR_FDS
78 The following additional environment variables are available:
80 - 'COLORED_STDERR_PRE'
81 String to write before each write to stderr, defaults to "\033[91m" (bright
83 - 'COLORED_STDERR_POST'
84 String to write after each write to stderr, defaults to "\033[0m" (reset
86 - 'COLORED_STDERR_FORCE_WRITE'
87 If set to an non-empty value add pre/post strings even when not writing to a
88 terminal, e.g. when writing to a file. By default, only writes to a terminal
95 To enable debug mode, configure coloredstderr with '--enable-debug'.
97 *Important:* Debug mode enables `assert()`s in the code which might abort the
98 process if an error condition is detected!
100 Debug mode is slower than normal mode. To log only warnings without the
101 overhead of debug mode use '--enable-warnings'. `assert()`s are not enabled
102 with '--enable-warnings', so it's safe to use.
104 Debug messages are written to the file `colored_stderr_debug_log.txt` in the
105 current working directory _if_ it exists. If it exists debug messages are
106 appended. Be careful, this file might grow very quickly.
108 *Important:* Warnings are written to `$HOME/colored_stderr_warning_log.txt`
109 even if it _does not_ exist (only if debug or warning mode is enabled)! If it
110 doesn't exist it's created. An existing file isn't overwritten, but the
111 warnings are appended at the end.
117 If you find any bugs not mentioned in this document please report them to
118 <simon@ruderich.org> with coloredstderr in the subject.
124 Written by Simon Ruderich <simon@ruderich.org>.
130 coloredstderr is licensed under GPL version 3 or later.
132 Copyright (C) 2013 Simon Ruderich
134 This program is free software: you can redistribute it and/or modify
135 it under the terms of the GNU General Public License as published by
136 the Free Software Foundation, either version 3 of the License, or
137 (at your option) any later version.
139 This program is distributed in the hope that it will be useful,
140 but WITHOUT ANY WARRANTY; without even the implied warranty of
141 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
142 GNU General Public License for more details.
144 You should have received a copy of the GNU General Public License
145 along with this program. If not, see <http://www.gnu.org/licenses/>.