---
title: nextflow log
description: Reference for the nextflow log command. Print the execution history and log information.
---

# `nextflow log`

Print the execution history and log information.

## Usage

```console
$ nextflow log [options] [run_name | session_id]
```

## Description

The `log` command queries the execution metadata of pipelines run by Nextflow. Run `nextflow log` with no arguments to list the previous runs. You can identify a run by either its run name or its session ID. Use the options below to filter and format the results when you debug a pipeline or inspect its execution metadata.

## Options

##### `-after`

Show log entries for runs executed *after* the specified one.

##### `-before`

Show log entries for runs executed *before* the specified one.

##### `-but`

Show log entries for all runs *except* the specified one.

##### `-f, -fields`

Comma-separated list of fields to include in the printed log.

The same fields as the `trace.fields` option can be specified here, as well as `stdout` and `stderr`. The trace fields `%cpu` and `%mem` must be specified as `pcpu` and `pmem`, respectively.

Use the `-l` option to see the complete list of available fields.

##### `-F, -filter`

Filter log entries by a custom expression, for example `process =~ /hello.*/ && status == 'COMPLETED'`.

##### `-h, -help`

Print the command usage.

##### `-l, -list-fields`

Show all available fields.

##### `-quiet`

Show only run names.

##### `-s`

Character used to separate column values.

##### `-t, -template`

Text template used to format each record in the log.

## Examples

List the execution logs of all previous runs in a project:

```console
$ nextflow log

TIMESTAMP           DURATION        RUN NAME        STATUS  REVISION ID     SESSION ID                              COMMAND
2020-10-07 11:52:24 2.1s            focused_payne   OK      96eb04d6a4      af6adaaa-ad4f-48a2-9f6a-b121e789adf5    nextflow run nextflow-io/hello -r master
2020-10-07 11:53:00 3.1s            tiny_leavitt    OK      e3b475a61b      4d3b95c5-4385-42b6-b430-c865a70d56a4    nextflow run ./tutorial.nf
2020-10-07 11:53:29 2.5s            boring_euler    OK      e3b475a61b      a6276975-7173-4208-ae09-ab9d6dce8737    nextflow run tutorial.nf
```

List only the *run names* of all previous runs in a project:

```console
$ nextflow log -quiet

focused_payne
tiny_leavitt
boring_euler
```

List the execution entries for a specific execution:

```console
$ nextflow log tiny_leavitt

work/1f/f1ea9158fb23b53d5083953121d6b6
work/bf/334115deec60929dc18edf0010032a
work/a3/06521d75da296d4dd7f4f8caaddad8
```

List the execution entries *after* a specific execution:

```console
$ nextflow log -after tiny_leavitt

work/92/c1a9cd9a96e0531d81ca69f5dc3bb7
work/3f/70944c7a549b6221e1ccc7b4b21b62
work/0e/2ebdba85f76f6068b21a1bcbf10cab
```

List the execution entries *before* a specific execution:

```console
$ nextflow log -before tiny_leavitt

work/5d/ad76f7b7ab3500cf616814ef644b61
work/c4/69a82b080a477612ba8d8e4c27b579
work/be/a4fa2aa38f76fd324958c81c2e4603
work/54/39116773891c47a91e3c1733aad4de
```

List the execution entries *except* for a specific execution:

```console
$ nextflow log -but tiny_leavitt

work/5d/ad76f7b7ab3500cf616814ef644b61
work/c4/69a82b080a477612ba8d8e4c27b579
work/be/a4fa2aa38f76fd324958c81c2e4603
work/54/39116773891c47a91e3c1733aad4de
```

Filter specific fields from the execution log of a process:

```console
$ nextflow log tiny_leavitt -f 'process,exit,hash,duration'

split_letters       0       1f/f1ea91       112ms
convert_to_upper    0       bf/334115       144ms
convert_to_upper    0       a3/06521d       139ms
```

Filter the execution log of a process with a custom expression:

```console
$ nextflow log tiny_leavitt -F 'process =~ /split_letters/'

work/1f/f1ea9158fb23b53d5083953121d6b6
```
