data_behind - Linux


data_behind is a Linux command that calculates the average delay between two events in a log file. It’s primarily used to analyze system performance and identify potential bottlenecks.


data_behind [OPTIONS] <in.log> <out.log>


| Flag | Description | Default |
| -d, –delimiter | Delimiter used to separate events (defaults to newline) | |
| -f, –field | Field numbers to analyze, separated by commas (defaults to all fields) | |
| -s, –separator | Separator used to separate fields (defaults to whitespace) | |


Calculate the average delay between REST API requests and responses:

data_behind -d "\n" in.log out.log

Analyze the delay in processing custom events with fields ‘arrival’ and ‘departure’:

data_behind -f 1,5 -s "," custom_events.log

Common Issues

  • Missing delimiter: Ensure the -d flag is specified correctly if your log file uses a non-standard delimiter.
  • Invalid field numbers: Check that the field numbers provided using the -f flag are valid for your log format.


Combine with ‘grep’: Filter logs before analysis to focus on specific events.

grep "error" in.log | data_behind out.log

Related Commands

  • uniq – Count repeated lines in a file
  • awk – Perform text processing and numerical computations