clogl - Linux


clogl is a command-line tool for generating log files in a simple, structured, and human-readable format. It provides a flexible way to capture, filter, and output log data, making it useful for debugging, monitoring, and analyzing applications.




  • -f, --file: Output to the specified file
  • -l, --level: Set the minimum log level to output
  • -s, --stdout: Output to the standard output
  • -h, --help: Display usage information


Filters specify which log messages to output. Multiple filters can be combined using logical operators.

Logical Operators

  • &&: AND
  • ||: OR
  • !: NOT

Message Properties

  • level: Log level (e.g., info, error)
  • source: Log source (e.g., package, class)
  • text: Log message text

Comparison Operators

  • =: Equals
  • !=: Not equals
  • >, <, >=, <=: Numeric comparisons


  • level >= error
  • source = "my_package"
  • text contains "keyword"


-f, --file

Specifies the file to output log messages to. If the file does not exist, it will be created.

-l, --level

Sets the minimum log level to output. Messages with a level lower than the specified level will be filtered out.

-s, --stdout

Outputs log messages to the standard output instead of a file.

-h, --help

Displays usage information.


Output the last 100 log messages to a file:

clogl -f /var/log/my_app.log -l debug

Filter log messages for a specific source and level:

clogl source = "my_app" level >= error

Output log messages to the standard output and filter by text:

clogl -s text contains "my_keyword"

Common Issues

Missing log file:

If you specify an invalid file path for output, clogl will fail with an error.

Invalid filter syntax:

Check for syntax errors in your filter expressions. Ensure that operators and property names are spelled correctly.


Log rotation:

clogl can be integrated with log rotation tools to automatically manage log files.

External data sources:

clogl can read log messages from external data sources such as syslog or a database by implementing a custom log reader.

Related Commands

  • logger: Sends log messages to syslog
  • syslog-ng: A powerful syslog daemon
  • grep: Filters text for patterns
  • sed: Performs text transformations