Skip to main content

nextflow logfile

Added in version 26.10

Print the contents of a Nextflow log file, with optional level filtering and follow mode.

Usage​

$ nextflow logfile [options] [run_name | session_id | path]

Description​

The logfile command prints the contents of a .nextflow.log file written by Nextflow during a pipeline run. The argument can be:

  • A run name, for example kickass_rutherford. Nextflow resolves it from the local execution history and matches it by session ID to the corresponding .nextflow.log[.N] file in the current directory.
  • A session ID, or a unique prefix of one, or the literal last for the most recent run.
  • A direct path to a log file, for example .nextflow.log.4 or an absolute path.

If you give no argument, logfile uses the most recent run.

Options​

-f, -follow​

Continuously print new lines as the file grows (similar to tail -f). Stop with Ctrl+C.

-h, -help​

Print the command usage.

-keep-ansi​

Preserve any ANSI escape sequences found inside log content. By default, Nextflow strips them to produce clean text.

-l, -level <LEVEL>​

Minimum log level to print: TRACE, DEBUG, INFO, WARN, or ERROR. Case-insensitive. When set, Nextflow prints only entries at this level or higher. Multi-line entries, such as stack traces, inherit the level of their parent entry. By default, Nextflow applies no filtering.

-n, -lines <N>​

Print only the last N log entries. Counts entries (one or more lines each), not raw lines.

-no-pager​

Do not pipe the output through a pager. By default, when standard output is a terminal, Nextflow pipes the output through $NXF_PAGER, then $PAGER, then less -FR. Nextflow adds -FR to a bare less invocation so that colors render. Short outputs exit without entering the pager. The -f/-follow option disables the pager.

-no-ansi​

Disable colored output. By default, when the output destination is a terminal:

  • Every line is prefixed with a colored 2-character level indicator.
  • TRACE and DEBUG entries are dimmed.
  • DEBUG, INFO, WARN and ERROR entries are syntax-highlighted to make them easier to read.

Nextflow disables styling when output goes to a non-terminal destination, such as a file or a pipe with -no-pager, or when the NO_COLOR environment variable is set.

Examples​

Print the log of the most recent run:

$ nextflow logfile

Print the log of a specific run, looked up by name:

$ nextflow logfile kickass_rutherford

Print a specific log file directly:

$ nextflow logfile .nextflow.log.4

Show only warnings and errors from the most recent run:

$ nextflow logfile -level WARN

Show the last 10 entries of an ongoing run and continue streaming new lines:

$ nextflow logfile -n 10 -f
On this Page