EXPLAIN.PY(1)              Annotate commands             EXPLAIN.PY(1)



NAME
       explain.py - Annotate commands using ASCII art

SYNOPSIS
       explain.py [-w WIDTH] [-c CHARS] [-s CHAR] [-r CHARS] [-j CHAR]
                  [-P PRESET] [-S] [-u] [-8] [-h]

DESCRIPTION
       explain.py allows you to explain commands using ASCII art.

OPTIONS
       -w WIDTH
       --width WIDTH
              Maximum width of output. Defaults to 72.

       -c CHARS
       --corner CHARS
              Characters to use as corners (overrides the preset). The
              default is “\- ”.

       -s CHAR
       --straight CHAR
              Character  to  use as straight lines (overrides the pre‐
              set). The default is “|”.

       -r CHARS
       --range CHARS
              Characters to use for ranges (overrides the preset). The
              default is “\_/”.

       -j CHAR
       --joint CHAR
              Character  to  use  for  joints between lines and ranges
              (overrides the preset). The default is “_”.

       -P PRESET
       --preset PRESET
              Use the specified preset list of box-drawing chars.  May
              be  one  of “ROUNDED“, “ASCII“, “BOLD“, “UNICODE“, “DOU‐
              BLE“ (case insensitive). Defaults to “ASCII“.

       -S
       --show-characters
              Only dump the symbol set and exit. Does not process  any
              input.

       -u
       --unicode
              Use  a  preset  of unicode glyphs for the graph. This is
              equivalent to “-P UNICODE”.

       -8
       --dont-force-utf-8
              Do not enforce UTF-8  as  output  encoding.  Let  Python
              decide.

       -h
       --help Show a brief help page.

SYNTAX AND EXAMPLES
       A basic example:

            vim -p .bashrc .vimrc
            --- -- --------------

            Open the editor.

            Open the files in tabs.

            Which files to open?

       Result:

            vim -p .bashrc .vimrc
            \_/ |  \____________/
             |  |         |
             |  |         \- Which files to open?
             |  |
             |  \- Open the files in tabs.
             |
             \- Open the editor.

       You  can  use  a “+” to end two adjacent ranges. Furthermore, a
       “!” will assign a comment to one single character. A more  com‐
       plex example:

            sed 's/hurz/herz/;p;q' < file
            ---  !-----+-----!!!!  ------

            Run sed.

            Replace ...

            ... hurz ...

            ... with herz.

            Separator.

            Print.

            Another separator.

            Quit.

            Read from this file. The shell will handle the redirection.

       Note that a “+” is optional if followed by a “!”.

       Result:

            sed 's/hurz/herz/;p;q' < file
            \_/  |\____/\___/||||  \____/
             |   |   |    |  ||||     |
             |   |   |    |  ||||     \- Read from this file. The shell will handle
             |   |   |    |  ||||        the redirection.
             |   |   |    |  ||||
             |   |   |    |  |||\- Quit.
             |   |   |    |  |||
             |   |   |    |  ||\- Another separator.
             |   |   |    |  ||
             |   |   |    |  |\- Print.
             |   |   |    |  |
             |   |   |    |  \- Separator.
             |   |   |    |
             |   |   |    \- ... with herz.
             |   |   |
             |   |   \- ... hurz ...
             |   |
             |   \- Replace ...
             |
             \- Run sed.

       Usually, all adjacent lines of comments will be merged into one
       single line. After that, it'll get wrapped to a  given  length.
       This  means, that manual line breaks will be lost. On the other
       hand, you may want to place manual line breaks. To do so, end a
       line with two backslashes:

            Number 1
            ------ -

            This is a very long line. There's a lot of text. It'll get wrapped
            automatically. Also note that there's line breaks inside of this
            comment. They'll be removed. This is the "traditional" way of handling
            comments.

            1: One! \\
            2: Two! \\
            3: Three! \\
            Now I added '\\' at the ends of those lines.
            That line, however, had no '\\' at its end. So, these two lines will
            become one single line and get wrapped properly.

       And this is what you get:

            Number 1
            \____/ |
               |   \- 1: One!
               |      2: Two!
               |      3: Three!
               |      Now I added '\\' at the ends of those lines. That line,
               |      however, had no '\\' at its end. So, these two lines will
               |      become one single line and get wrapped properly.
               |
               \- This is a very long line. There's a lot of text. It'll get wrapped
                  automatically. Also note that there's line breaks inside of this
                  comment. They'll be removed. This is the "traditional" way of
                  handling comments.

       You can explain several commands in one single source file.

DEVELOPER INFO: TEST CASES
       There's  a  basic  test suite available that can be run as fol‐
       lows:

            $ cd ~/git/explain/tests
            $ ./suite.sh

       A test case is a short bash(1) script whose filename  must  end
       with .test:

            # Complete command line. This is a Bash array.
            cmd=("$program" '-j' '+')

            # Notes:
            # - These here-documents don't have a final newline on the very last
            #   line. Hence, the "echo" calls in "suite.sh" must NOT add a "-n".

            read -rd '' input <<"EOF"
            ed .profile
            -- --------
            Editor.

            File to edit.
            EOF

            read -rd '' expected_output <<"EOF"
            ed .profile
            |  \___+__/
            |      |
            |      \- File to edit.
            |
            \- Editor.
            EOF

       As you can see, it consists of three variables:

       ·   cmd: The complete command line as a bash(1) array.

       ·   input: The input that is fed to explain.py.

       ·   expected_output: What explain.py must print for the test to
           succeed.

       Furthermore, there's a file called global_settings.sh. In  this
       file, $program is defined.

BUGS
       Please          report          bugs         at         GitHub:
       https://github.com/vain/explain/issues.

LICENSE
       This is “PIZZA-WARE”, basically. See LICENSE for details.

AUTHORS
       For the most up to date list, clone the source  repository  and
       do  a  git  shortlog.  As of now, the core was written by Peter
       Hofmann (pcode@uninformativ.de), some improvements were made by
       tiwo.

SEE ALSO
       python2(1), bash(1)



explain.py                   February 2012               EXPLAIN.PY(1)