pycolor-term 0.1.0

Execute commands, coloring terminal output in real-time using ANSI color codes.

Pycolor

1. Installation.
2. Example Usage.
3. Configuration.
4. Formatting Strings.
   • Color Formatting.
   • Field Formatting.
   • Group Formatting.
   • Alignment.
   • Truncate.
5. Debugging and Creating Profiles.
   • Debug Colors.
   • Creating Profiles.
6. Limitations.
7. Known Issues.

A Python program that executes commands to perform real-time terminal output coloring using ANSI color codes. Color formatting can be added to program output using JSON configuration files and regular expressions to improve readability of the output.

Designed for Unix, but works in Windows.

Installation

pip install pycolor-term

Example Usage

Pycolor can be used explicitly on the command line:

Before:

After:

Sample df configuration file.

---

Pycolor can also be aliased in ~/.bashrc like so:

alias rsync='pycolor rsync'

Before:

After: Note pycolor omitted lines with trailing slashes in addition to coloring output for better readability.

Sample rsync configuration file.

---

Sample rclone copy output:

Before:

After:

Configuration

Pycolor will first try to load configuration from ~/.pycolor.json before loading files found in ~/.pycolor.d/ in filename order.

When looking for a profile to use, pycolor will select the last matching profile based on the name/command, name_expression/command_expression, or which property.

Matching patterns are applied first-to-last for each profile.

JSON schema files that describe the config format can be found in /config/schema/.

Sample config files can be found here and will be automatically copied to ~/.pycolor.d/ when run, if it does not exist.

Formatting Strings

Use formatting strings to color/manipulate the program output in real-time. These are valid formats:

• %(<name>:<value>)
• %<code>(<value>)
• %<code><value>

Code	Name	Description
C	color	Color formatter
F	field	Field (separator) formatter
G	group	Regex group formatter
H	colorctx	Context-aware field/group color alias
	align	Alignment formatter
	trunc	Truncation formatter

Formatting strings can written like %(color:red), %C(red), or %Cr. %C(red)hello formats the string hello in red.

A literal % can be used in a format string by using %%. E.g. the format string The total is %C(red)15%% will become The total is 15%, with the 15% part in red.

Valid format value characters are upper/lowercase letters and numbers, unless the argument is encapsulated in parentheses, then everything in the parenthesis pair is used.

Check the sample config for examples of formatting strings being used for actual programs.

Colors

To colorize output through a replace pattern use %(color:<color value>), %C(<color value>) or %C<color value>.

Recognized Attributes and Colors:

Color Value	Aliases	ANSI Code	Description
reset	normal, res, nor, z	\e[0m	Resets all ANSI color formatting
bold	bright, bol, bri	\e[1m	Bold characters
dim		\e[2m	Dim characters
italic	ita	\e[3m	Italicize characters
underline	underlined, ul, und	\e[4m	Underline characters
blink	bli	\e[5m	Blink characters
invert	reverse, inv, rev	\e[7m	Invert background and foreground colors
hidden	conceal, hid, con	\e[8m	Hide characters
strikethrough	strike, str, crossedout, crossed, cro	\e[9m	Strikethrough characters
black	k	\e[30m	Black color
red	r	\e[31m	Red color
green	g	\e[32m	Green color
yellow	y	\e[33m	Yellow color
blue	b	\e[34m	Blue color
magenta	m	\e[35m	Magenta color
cyan	c	\e[36m	Cyan color
grey	gray, e	\e[37m	Grey color
default		\e[39m	Default color
overline	overlined, ol, ove	\e[53m	Overline characters
darkgrey	darkgray, de, lk	\e[90m	Dark grey color
lightred	lr	\e[91m	Light red color
lightgreen	lg	\e[92m	Light green color
lightyellow	ly	\e[93m	Light yellow color
lightblue	lb	\e[94m	Light blue color
lightmagenta	lm	\e[95m	Light magenta color
lightcyan	lc	\e[96m	Light cyan color
white	lightgrey, le, w	\e[97m	White color

Click here for a list of all attributes and color codes.

Modifier Characters

You can select multiple color values by separating them with ; (must be wrapped in parentheses). e.g. %(color:bold;red) or %C(bold;red).

If ^ is added before a color (e.g. %C(^red)), it will set the background color instead. The color formatting for bold, red-on-yellow text can be written as %C(bold;red;^yellow)hello%C(z), or %C(bol;r;^y)hello%Cz, which will produce \e[1;31;43mhello\e[0m.

If ^ is added before a style (e.g. %C(^italic) produces \e[23m), then the style is turned off.

Note that turning off bold (%C(^bold) i.e. \e[21m) instead turns on double underline for some terminals.

Special Colors

8-bit Color

If a color value is just a number (e.g. %C130), then it will use the 8-bit color set (in this case, a brown color: \e[38;5;130m). This also works for background colors as well (e.g. %C(^130) produces \e[48;5;130m).

Click here to see the 8-bit color table.

24-bit Color

24-bit color is also supported by using hex codes (%C(0xffaa00) or %C(0xfa0) will produce orange: \e[38;2;255;170;0m).

Raw ANSI Codes

If for some reason you would like to use raw color codes, %C(raw1;3;36) will produce bold, italic, cyan (\e[1;3;36m).

Fields

If the pattern's separator property is set, then the fields and their separators can be referenced in the format string.

To get a field's text, use %F<field number>.

To get the field separator string, use %Fs<field number>. This will return the field separator string that precedes that field number. (e.g. %Fs3 will get the field separator string that comes before the third field %F3).

If separator is set to #+, and the output line is a#b##c###d##e#f, the field format values will be:

Field Format	Value
%F1	a
%Fs2	#
%F2	b
%Fs3	##
%F3	c
%Fs4	###
%F4	d
%Fs5	##
%F5	e
%Fs6	#
%F6	f

Negative Indexing

Field formats support negative indexing, so %F(-1)_%F(-2) will format to f_e in the previous example.

Field Ranges

Giving a range of fields is possible using the * character, in the format %F(<start range>*<end range>).

Using the same example as above:

Field Format	Value
%F(*3)	a#b##c
%F(1*3)	a#b##c
%F(2*3)	b##c
%F(2*4)	b##c###d
%F(4*)	d##e#f

Separator replacement

If you want to format using field ranges, but want to override the separator used to be a constant-length string, use %F(<start range>*<end range>,<separator>). Using the previous input as an example, %F(*4,_) formats to a_b_c_d.

replace-fields

Changing only the matched fields is possible using pattern's replace-fields property. Any fields not explicitly set will be left alone.

Use %Fc to specify the current field that applies to the index/string.

It can be a list of format strings, where the format string at index i is applied to field number i + 1.

'replace_fields': ["%Cg%Fc%Cz", "%Cr%Fc%Cz", "%Cg%Fc%Cz"]

It can also be an object with the keys as field numbers and the value as the format value. Keys may be comma-separated numbers, or even ranges ("<start>*<end>" or "<start>*<end>*<step>").

'replace_fields': {
    "1,3": "%Cg%Fc%Cz",
    "2": "%Cr%Fc%Cz",
    "4*6": "%Cb%Fc%Cz"
}

Groups

Regex groups can be referenced with the format: %G<group number or name>. %G0 is the entire matching text from expression. %G1 is the first matching group, %G2 is the second, etc. If the regex group is named, it can also be referenced by name (e.g. %G(myregexgroup)).

Group Incrementor

Instead of using groups explicitly in order (e.g. %G1, %G2: %G3), using the special incrementor instead of numbers, %Gn, %Gn: %Gn, will result in the same format output.

Note that if a named group n is defined in the expression, then the special incrementor will be overridden.

replace-groups

Changing only the matched regex groups is possible using pattern's replace-groups property. Any groups not explicitly set will be left alone.

Use %Gc to specify the current group that applies to the index/strin.

It can be a list of format strings, where the format string at index i is applied to group number i + 1.

'replace_groups': ["%Cg%Gc%Cz", "%Cr%Gc%Cz", "%Cg%Gc%Cz"]

It can also be an object with the keys as group numbers and the value as the format value. Keys may be comma-separated numbers, or even ranges ("<start>*<end>" or "<start>*<end>*<step>").

'replace_groups': {
    "1,3": "%Cg%Gc%Cz",
    "2": "%Cr%Gc%Cz",
    "4*6": "%Cb%Fc%Cz"
}

Context-Aware Color Alias Format

You may find yourself coloring groups or fields often using %Cg%Fc%Cz or %Cg%Gc%Cz, which is why a context-aware color alias format is available: %H(<color value>) is an alias for %C(<color value>)%Fc%Cz or %C(<color value>)%Gc%Cz.

Now %Cg%Gc%Cz can be replaced with the shorter alias %Hg. If %H is used in replace_groups, it will be an alias for coloring %Gc, and if %H is used in replace_fields, it will be an alias for coloring %Fc.

Alignment

Align strings to a certain width with %(align:<width>,<position>,<pad character>)<string>%(end).

Value	Description
width	align string to this width
position	alignment position: left, middle, or right (default left)
pad character	pad character used to pad the string to width (default )

The text will be padded to the width specified. If the width is shorter than the text, then no padding or alignment is done.

For example, left-aligning group 1 with a 12 character width can be done with the format string %(align:12)%G1%(end).

Right-aligning can be done with %(align:12,right)%G1%(end).

Truncate

Truncate strings to a certain length using %(trunc:<length>,<location>,<replace>,<hard length>)<string>%(end), where:

Value	Description
length	truncate string to this length
location	where to truncate string: left, middle, or right
replace	insert this string at the truncation (e.g ...) (default empty)
hard length	indicates if length of replace is counted as part of length: yes or no (default yes)

Truncate Samples

Truncate the value of group 1 to 8 chars, adding ... if necessary: %(trunc:8,right,...,no)%G1%(end).

String	Result
Testing	Testing
LongString	LongStri...

Truncate the value of a path in field 1 to 16 chars, inserting ... if necessary: %(trunc:16,middle,...)%F1%(end).

String	Result
/root/	/root/
/path/to/a/certain/file	/path/...in/file

Debugging and Creating Profiles

Debug Colors

To check the supported color codes of your terminal, run pycolor --debug-color to print all the available ANSI color codes. Using --debug-color will show the results of the text styles, 16-color output, 8-bit color support, and 24-bit color support.

Output of pycolor --debug-color run on Windows PowerShell (24-bit colors are not shown in this image for brevity):

Note: bold off (\e[21m) is actually bold underline in PowerShell

Creating Profiles

Pycolor has a debug mode when running commands that shows the raw output of the command. Debug mode is turned on using -v or --verbose and can be used multiple times to increase the debug level.

Debug levels (previous levels are applied to the current):

Level	Command	Description
1	-v	Print received output
2	-vv	Print final output written
3	-vvv	Print each matching pattern index and its output
4	-vvvv	Print the output line number

Using debug level 3 on free -h with a profile loaded:

Limitations

• Programs that expect interactive standard input may not work properly.
• Programs that rewrite parts of the screen may cause unexpected behavior.

Known Issues

• A fatal Python error can occur when attempting to acquire a lock for stdout at interpreter shutdown, caused when the command pycolor is running terminates, but output has not yet fully been written to the screen.
  • It has only been observed when running pycolor inside of tmux while in copy-mode.