dc is a command-line utility that enhances terminal output by adding colorization. It's designed to highlight common data formats like XML and JSON, as well as patterns such as log levels and timestamps.
You can use dc in two main ways:
- As a command wrapper:
dc your_command [args...]dcexecutesyour_commandand colorizes its standard output.
- As a pipe processor:
your_command | dcdcreads data from standard input (stdin), colorizes it, and prints it to standard output (stdout).
npm i -g @s-a/digital-colors(dc your_command [args...])
When you provide dc with a command to run, it executes that command, captures its standard output, and applies colorization before printing it to your terminal.
Key Characteristics:
- The first argument after
dcis the command to be executed (e.g.,tail,ls,cat). - Any subsequent arguments are passed directly to that command.
- This mode is ideal for colorizing the output of commands directly, including long-running processes like
tail -f.
Examples:
-
Live Log Monitoring (most common use case): To monitor a log file with
tail -fand have its output colorized:dc tail -f /path/to/your/logfile.log
(For Windows, use appropriate paths like
D:\\log\\api.log) -
Colorizing Output of Short-Lived Commands:
dc ls -la
dc cat /etc/hosts
(your_command | dc)
dc can also process data piped to its standard input. This allows you to colorize the output of any command that writes to stdout.
Key Characteristics:
dcreads data line by line (or in chunks) from stdin.- It applies colorization to the received data.
- The colorized data is then printed to stdout.
- This mode is useful when you want to take the output of an existing command and pass it through
dcfor colorization.
Examples:
- Colorizing the output of
cat:cat myapplication.log | dc - Colorizing the output of
grep:grep "ERROR" system.log | dc
- Colorizing a JSON string from
echo:echo '{"name": "example", "value": 123}' | dc
It's important to understand how dc behaves when used in command pipelines to avoid confusion:
-
dc your_command [args...] | another_command(Piping fromdcwhendcwraps a command):dcfirst executesyour_commandand colorizes its output.- This colorized output (including ANSI escape codes) is then piped to
another_command. - Example:
dc tail -f my.log | grep "ERROR"will pass colorized lines togrep. This might be useful ifanother_commandcan handle ANSI codes (likeless -R), but oftengrepwould be better used beforedcif you want to filter first, then colorize (see Mode 2).
-
dc | another_command(Piping fromdcwhendchas no command to run):- If
dcis used as the first command in a pipeline without being given its own command to execute (e.g.,dc | grep foo), it defaults to Mode 2 behavior: it will read from its standard input. - If stdin is your terminal,
dcwill wait for you to type something. What you type will be colorized and then passed toanother_command. - This is why
dc | tail -f /path/to/logfile.logdoes not work as expected for live log monitoring. In this case,dcwaits for stdin, andtail -fwould attempt to process whatever (if anything)dcoutputs, rather thandcprocessingtail -f's file monitoring output. - Correct for live log monitoring:
dc tail -f /path/to/logfile.log(Mode 1).
- If
-
your_command | dc | another_command(Piping throughdc):your_commandsends its output todc.dccolorizes this output (Mode 2).- The colorized output from
dcis then piped toanother_command. - Example:
cat my.log | dc | grep "ERROR"(again,grepwill operate on colorized text).
General Tip for Piping: If you want to filter or process text before colorization, do it before piping to dc (e.g., grep "ERROR" my.log | dc). If you want to filter or process the colorized text, pipe from dc (e.g., dc tail -f my.log | less -R).