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Name

nix top - interactively show active builds

Synopsis

nix top [option…]

Examples

  • Show the active builds:

    # nix top
nix top - 14:02:17  2 builds, 6 processes, 812.4% CPU, 454.8 MiB RSS
USER          PID   %CPU    TIME        RSS  WALL  DERIVATION/COMMAND
nixbld11  3534394  790.3  110.2s  438.6 MiB   48s  /nix/store/lzvdxlbr6xjd9w8py4nd2y2nnqb9gz7p-nix-util-tests-3.13.2.drv
nixbld11  3534394    0.0    0.8s    3.9 MiB        └───bash -e /nix/store/jwqf79…-source-stdenv.sh
nixbld11  3534751    1.5   36.3s    7.5 MiB            └───ninja -j24
nixbld11  3535637   98.0    4.1s  208.1 MiB                ├───g++ -fPIC
nixbld11  3535658   99.5    3.0s  215.0 MiB                └───g++ -fPIC
nixbld1   3534377   22.1    1.8s   16.2 MiB    5s  /nix/store/nh2dx9cqcy9lw4d4rvd0dbsflwdsbzdy-patchelf-0.18.0.drv
nixbld1   3534377    0.0    1.8s    4.2 MiB        └───bash -e /nix/store/xk05lk…-default-builder.sh

Description

This command shows the currently running Nix builds in a continuously updating full-screen view, similar to top. It shows the same information as nix ps, plus the CPU usage of each build and process since the previous update.

The columns are:

  • USER: The user that the process runs as.
  • PID: The process ID.
  • %CPU: CPU usage since the previous update. 100% corresponds to one fully used CPU core.
  • TIME: Total CPU time consumed. For a process, this includes the CPU time of its reaped children.
  • RSS: Resident memory. For a build, this is taken from its cgroup if available (counting shared pages once); otherwise it’s the sum of the RSS of its processes.
  • WALL: How long the build has been running.
  • DERIVATION/COMMAND: The derivation being built, or the command line of a process in the build.

The following keys are supported:

  • q, Ctrl-C: Quit.
  • ↑/↓, k/j: Scroll one line.
  • PgUp/PgDn: Scroll one page.
  • Home/End, g/G: Scroll to the top or bottom.
  • t, Enter: Toggle between showing the processes of each build and showing only the builds.
  • c: Toggle compact mode (enabled by default). This shows only the program name rather than the full path of the executable of each process (e.g. g++ instead of /nix/store/…/bin/g++), and abbreviates the hash parts of other store paths in command lines (e.g. /nix/store/2limljgc50jy76vg388ldgggcjhhkhav-gcc-15.2.0 is shown as /nix/store/2limlj…-gcc-15.2.0).
  • s: Cycle the sort order of builds: by CPU usage, by RSS, by wall time, or by name.
  • +/-: Increase or decrease the refresh interval by 0.5 seconds (default 2 seconds).
  • Space: Refresh now.
  • Ctrl-L: Redraw the screen.

Options

  • --debug

    Set the logging verbosity level to ‘debug’.

  • --log-format format

    Set the format of log output; one of raw, internal-json, bar or bar-with-logs.

  • --print-build-logs / -L

    Print full build logs on standard error.

  • --quiet

    Decrease the logging verbosity level.

  • --verbose / -v

    Increase the logging verbosity level.

Miscellaneous global options

  • --help

    Show usage information.

  • --offline

    Disable substituters and consider all previously downloaded files up-to-date.

  • --option name value

    Set the Nix configuration setting name to value (overriding nix.conf).

  • --refresh

    Consider all previously downloaded files out-of-date.

  • --version

    Show version information.

Note

See man nix.conf for overriding configuration settings with command line flags.