nix/doc/manual/source/command-ref/nix-env.md

Name

nix-env - manipulate or query Nix user environments

Synopsis

nix-env operation [options] [arguments…] [--option name value] [--arg name value] [--argstr name value] [{--file | -f} path] [{--profile | -p} path] [--system-filter system] [--dry-run]

Description

The command nix-env is used to manipulate Nix user environments. User environments are sets of software packages available to a user at some point in time. In other words, they are a synthesised view of the programs available in the Nix store. There may be many user environments: different users can have different environments, and individual users can switch between different environments.

nix-env takes exactly one operation flag which indicates the subcommand to be performed. The following operations are available:

• --install
• --upgrade
• --uninstall
• --set
• --set-flag
• --query
• --switch-profile
• --list-generations
• --delete-generations
• --switch-generation
• --rollback

These pages can be viewed offline:

• man nix-env-<operation>.

  Example: man nix-env-install

• nix-env --help --<operation>

  Example: nix-env --help --install

Package sources

nix-env can obtain packages from multiple sources:

• An attribute set of derivations from:
  • The default Nix expression (by default)
  • A Nix file, specified via --file
  • A profile, specified via --from-profile
  • A Nix expression that is a function which takes default expression as argument, specified via --from-expression
• A store path

Selectors

Several operations, such as nix-env --query and nix-env --install, take a list of arguments that specify the packages on which to operate.

Packages are identified based on a name part and a version part of a symbolic derivation name:

• name: Everything up to but not including the first dash (-) that is not followed by a letter.
• version: The rest, excluding the separating dash.

Example

nix-env parses the symbolic derivation name apache-httpd-2.0.48 as:

{
  "name": "apache-httpd",
  "version": "2.0.48"
}

Example

nix-env parses the symbolic derivation name firefox.* as:

{
  "name": "firefox.*",
  "version": ""
}

The name parts of the arguments to nix-env are treated as extended regular expressions and matched against the name parts of derivation names in the package source. The match is case-sensitive. The regular expression can optionally be followed by a dash (-) and a version number; if omitted, any version of the package will match. For details on regular expressions, see regex(7).

Example

Common patterns for finding package names with nix-env:

• firefox

  Matches the package name firefox and any version.

• firefox-32.0

  Matches the package name firefox and version 32.0.

• gtk\\+

  Matches the package name gtk+. The + character must be escaped using a backslash (\) to prevent it from being interpreted as a quantifier, and the backslash must be escaped in turn with another backslash to ensure that the shell passes it on.

• .\*

  Matches any package name. This is the default for most commands.

• '.*zip.*'

  Matches any package name containing the string zip. Note the dots: '*zip*' does not work, because in a regular expression, the character * is interpreted as a quantifier.

• '.*(firefox|chromium).*'

  Matches any package name containing the strings firefox or chromium.

Files

nix-env operates on the following files.

{{#include ./files/default-nix-expression.md}}

{{#include ./files/profiles.md}}