Bash:
Logging

How to:

In Bash, logging can be as simple as redirecting or appending output to a file. Here’s a basic example:

echo "Starting the script..." >> script.log
# Your script commands here
echo "Script completed on $(date)" >> script.log

For something more advanced, you could incorporate syslog for system-wide logging:

logger "Custom message from my script"

logger sends a log message to the syslog service, which then handles it according to the system’s syslog configuration.

Sample output captured in script.log:

Starting the script...
Script completed on Tue Mar 23 09:26:35 PDT 2021

Deep Dive

Historically in Unix-like systems, logging has been facilitated by the syslog service, allowing different applications and parts of the system to log messages centrally. This allows for the implementation of a standardized logging mechanism throughout the system.

When it comes to alternatives, some may look into using syslog-ng or rsyslog for more advanced logging features, or writing logs to a time-series database for analytical purposes. For applications with higher levels of complexity, using a dedicated logging library or application like Log4j (in the Java ecosystem) or Monolog (in PHP), which can provide structured and configurable logging options, could make sense even for a scripting language like Bash.

The way you implement logging depends greatly on your application’s requirements. If you just need simple output to track script progress, appending messages to a file is easy and convenient. However, for more scalable and robust logging, you’ll want to integrate with a logging system that supports features like log rotation, log levels, and remote logging.

See Also

• The man pages for the logger and syslog functions are always your friend, try man logger or man syslog.
• For an in-depth look at system logging, consider reading the rsyslog and syslog-ng documentation.
• To find out more about the historical context and principles behind logging in Unix-like systems, the Syslog protocol documented in RFC 5424 provides comprehensive information.