Merge remote-tracking branch 'origin/master' into auto-uid-allocation

8 files changed, 63 insertions, 51 deletions

diff --git a/doc/manual/src/command-ref/env-common.md b/doc/manual/src/command-ref/env-common.md
index 6e2403461..3f3eb6915 100644
--- a/doc/manual/src/command-ref/env-common.md
+++ b/doc/manual/src/command-ref/env-common.md
@@ -2,11 +2,11 @@
 
 Most Nix commands interpret the following environment variables:
 
-  - `IN_NIX_SHELL`\
+  - [`IN_NIX_SHELL`]{#env-IN_NIX_SHELL}\
     Indicator that tells if the current environment was set up by
-    `nix-shell`. Since Nix 2.0 the values are `"pure"` and `"impure"`
+    `nix-shell`. It can have the values `pure` or `impure`.
 
-  - `NIX_PATH`\
+  - [`NIX_PATH`]{#env-NIX_PATH}\
     A colon-separated list of directories used to look up Nix
     expressions enclosed in angle brackets (i.e., `<path>`). For
     instance, the value
@@ -44,7 +44,7 @@ Most Nix commands interpret the following environment variables:
     The Nix search path can also be extended using the `-I` option to
     many Nix commands, which takes precedence over `NIX_PATH`.
 
-  - `NIX_IGNORE_SYMLINK_STORE`\
+  - [`NIX_IGNORE_SYMLINK_STORE`]{#env-NIX_IGNORE_SYMLINK_STORE}\
     Normally, the Nix store directory (typically `/nix/store`) is not
     allowed to contain any symlink components. This is to prevent
     “impure” builds. Builders sometimes “canonicalise” paths by
@@ -66,41 +66,41 @@ Most Nix commands interpret the following environment variables:
 
     Consult the mount 8 manual page for details.
 
-  - `NIX_STORE_DIR`\
+  - [`NIX_STORE_DIR`]{#env-NIX_STORE_DIR}\
     Overrides the location of the Nix store (default `prefix/store`).
 
-  - `NIX_DATA_DIR`\
+  - [`NIX_DATA_DIR`]{#env-NIX_DATA_DIR}\
     Overrides the location of the Nix static data directory (default
     `prefix/share`).
 
-  - `NIX_LOG_DIR`\
+  - [`NIX_LOG_DIR`]{#env-NIX_LOG_DIR}\
     Overrides the location of the Nix log directory (default
     `prefix/var/log/nix`).
 
-  - `NIX_STATE_DIR`\
+  - [`NIX_STATE_DIR`]{#env-NIX_STATE_DIR}\
     Overrides the location of the Nix state directory (default
     `prefix/var/nix`).
 
-  - `NIX_CONF_DIR`\
+  - [`NIX_CONF_DIR`]{#env-NIX_CONF_DIR}\
     Overrides the location of the system Nix configuration directory
     (default `prefix/etc/nix`).
 
-  - `NIX_CONFIG`\
+  - [`NIX_CONFIG`]{#env-NIX_CONFIG}\
     Applies settings from Nix configuration from the environment.
     The content is treated as if it was read from a Nix configuration file.
     Settings are separated by the newline character.
 
-  - `NIX_USER_CONF_FILES`\
+  - [`NIX_USER_CONF_FILES`]{#env-NIX_USER_CONF_FILES}\
     Overrides the location of the user Nix configuration files to load
     from (defaults to the XDG spec locations). The variable is treated
     as a list separated by the `:` token.
 
-  - `TMPDIR`\
+  - [`TMPDIR`]{#env-TMPDIR}\
     Use the specified directory to store temporary files. In particular,
     this includes temporary build directories; these can take up
     substantial amounts of disk space. The default is `/tmp`.
 
-  - `NIX_REMOTE`\
+  - [`NIX_REMOTE`]{#env-NIX_REMOTE}\
     This variable should be set to `daemon` if you want to use the Nix
     daemon to execute Nix operations. This is necessary in [multi-user
     Nix installations](../installation/multi-user.md). If the Nix
@@ -108,16 +108,16 @@ Most Nix commands interpret the following environment variables:
     should be set to `unix://path/to/socket`. Otherwise, it should be
     left unset.
 
-  - `NIX_SHOW_STATS`\
+  - [`NIX_SHOW_STATS`]{#env-NIX_SHOW_STATS}\
     If set to `1`, Nix will print some evaluation statistics, such as
     the number of values allocated.
 
-  - `NIX_COUNT_CALLS`\
+  - [`NIX_COUNT_CALLS`]{#env-NIX_COUNT_CALLS}\
     If set to `1`, Nix will print how often functions were called during
     Nix expression evaluation. This is useful for profiling your Nix
     expressions.
 
-  - `GC_INITIAL_HEAP_SIZE`\
+  - [`GC_INITIAL_HEAP_SIZE`]{#env-GC_INITIAL_HEAP_SIZE}\
     If Nix has been configured to use the Boehm garbage collector, this
     variable sets the initial size of the heap in bytes. It defaults to
     384 MiB. Setting it to a low value reduces memory consumption, but
diff --git a/doc/manual/src/command-ref/nix-build.md b/doc/manual/src/command-ref/nix-build.md
index 43de7a6e6..49c6f3f55 100644
--- a/doc/manual/src/command-ref/nix-build.md
+++ b/doc/manual/src/command-ref/nix-build.md
@@ -12,6 +12,12 @@
   [`--dry-run`]
   [{`--out-link` | `-o`} *outlink*]
 
+# Disambiguation
+
+This man page describes the command `nix-build`, which is distinct from `nix
+build`. For documentation on the latter, run `nix build --help` or see `man
+nix3-build`.
+
 # Description
 
 The `nix-build` command builds the derivations described by the Nix
@@ -47,16 +53,16 @@ All options not listed here are passed to `nix-store
 --realise`, except for `--arg` and `--attr` / `-A` which are passed to
 `nix-instantiate`.
 
-  - `--no-out-link`\
+  - [`--no-out-link`]{#opt-no-out-link}\
     Do not create a symlink to the output path. Note that as a result
     the output does not become a root of the garbage collector, and so
     might be deleted by `nix-store
                     --gc`.
 
-  - `--dry-run`\
+  - [`--dry-run`]{#opt-dry-run}\
     Show what store paths would be built or downloaded.
 
-  - `--out-link` / `-o` *outlink*\
+  - [`--out-link`]{#opt-out-link} / `-o` *outlink*\
     Change the name of the symlink to the output path created from
     `result` to *outlink*.
 
diff --git a/doc/manual/src/command-ref/nix-copy-closure.md b/doc/manual/src/command-ref/nix-copy-closure.md
index 7047d3012..9a29030bd 100644
--- a/doc/manual/src/command-ref/nix-copy-closure.md
+++ b/doc/manual/src/command-ref/nix-copy-closure.md
@@ -30,8 +30,8 @@ Since `nix-copy-closure` calls `ssh`, you may be asked to type in the
 appropriate password or passphrase.  In fact, you may be asked _twice_
 because `nix-copy-closure` currently connects twice to the remote
 machine, first to get the set of paths missing on the target machine,
-and second to send the dump of those paths.  If this bothers you, use
-`ssh-agent`.
+and second to send the dump of those paths.  When using public key
+authentication, you can avoid typing the passphrase with `ssh-agent`.
 
 # Options
 
diff --git a/doc/manual/src/command-ref/nix-env.md b/doc/manual/src/command-ref/nix-env.md
index 8d6abaf52..a5df35d77 100644
--- a/doc/manual/src/command-ref/nix-env.md
+++ b/doc/manual/src/command-ref/nix-env.md
@@ -31,7 +31,7 @@ subcommand to be performed. These are documented below.
 Several commands, such as `nix-env -q` and `nix-env -i`, take a list of
 arguments that specify the packages on which to operate. These are
 extended regular expressions that must match the entire name of the
-package. (For details on regular expressions, see regex7.) The match is
+package. (For details on regular expressions, see **regex**(7).) 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. Here are some examples:
@@ -198,7 +198,7 @@ a number of possible ways:
     another.
 
   - If `--from-expression` is given, *args* are Nix
-    [functions](../expressions/language-constructs.md#functions)
+    [functions](../language/constructs.md#functions)
     that are called with the active Nix expression as their single
     argument. The derivations returned by those function calls are
     installed. This allows derivations to be specified in an
@@ -412,7 +412,7 @@ The upgrade operation determines whether a derivation `y` is an upgrade
 of a derivation `x` by looking at their respective `name` attributes.
 The names (e.g., `gcc-3.3.1` are split into two parts: the package name
 (`gcc`), and the version (`3.3.1`). The version part starts after the
-first dash not followed by a letter. `x` is considered an upgrade of `y`
+first dash not followed by a letter. `y` is considered an upgrade of `x`
 if their package names match, and the version of `y` is higher than that
 of `x`.
 
diff --git a/doc/manual/src/command-ref/nix-instantiate.md b/doc/manual/src/command-ref/nix-instantiate.md
index 2e198daed..8f143729e 100644
--- a/doc/manual/src/command-ref/nix-instantiate.md
+++ b/doc/manual/src/command-ref/nix-instantiate.md
@@ -51,7 +51,7 @@ standard input.
   - `--strict`\
     When used with `--eval`, recursively evaluate list elements and
     attributes. Normally, such sub-expressions are left unevaluated
-    (since the Nix expression language is lazy).
+    (since the Nix language is lazy).
 
     > **Warning**
     >
@@ -66,7 +66,7 @@ standard input.
     When used with `--eval`, print the resulting value as an XML
     representation of the abstract syntax tree rather than as an ATerm.
     The schema is the same as that used by the [`toXML`
-    built-in](../expressions/builtins.md).
+    built-in](../language/builtins.md).
 
   - `--read-write-mode`\
     When used with `--eval`, perform evaluation in read/write mode so
diff --git a/doc/manual/src/command-ref/nix-shell.md b/doc/manual/src/command-ref/nix-shell.md
index a2b6d8a8e..840bccd25 100644
--- a/doc/manual/src/command-ref/nix-shell.md
+++ b/doc/manual/src/command-ref/nix-shell.md
@@ -15,6 +15,12 @@
   [`--keep` *name*]
   {{`--packages` | `-p`} {*packages* | *expressions*} … | [*path*]}
 
+# Disambiguation
+
+This man page describes the command `nix-shell`, which is distinct from `nix
+shell`. For documentation on the latter, run `nix shell --help` or see `man
+nix3-shell`.
+
 # Description
 
 The command `nix-shell` will build the dependencies of the specified
diff --git a/doc/manual/src/command-ref/nix-store.md b/doc/manual/src/command-ref/nix-store.md
index 7db9f0c1c..ecd838e8d 100644
--- a/doc/manual/src/command-ref/nix-store.md
+++ b/doc/manual/src/command-ref/nix-store.md
@@ -22,7 +22,7 @@ This section lists the options that are common to all operations. These
 options are allowed for every subcommand, though they may not always
 have an effect.
 
-  - `--add-root` *path*\
+  - [`--add-root`]{#opt-add-root} *path*\
     Causes the result of a realisation (`--realise` and
     `--force-realise`) to be registered as a root of the garbage
     collector. *path* will be created as a symlink to the resulting
@@ -121,7 +121,7 @@ Special exit codes:
   - `102`\
     Hash mismatch, the build output was rejected because it does not
     match the [`outputHash` attribute of the
-    derivation](../expressions/advanced-attributes.md).
+    derivation](../language/advanced-attributes.md).
 
   - `104`\
     Not deterministic, the build succeeded in check mode but the
diff --git a/doc/manual/src/command-ref/opt-common.md b/doc/manual/src/command-ref/opt-common.md
index 7ee1a26bc..e612c416f 100644
--- a/doc/manual/src/command-ref/opt-common.md
+++ b/doc/manual/src/command-ref/opt-common.md
@@ -2,13 +2,13 @@
 
 Most Nix commands accept the following command-line options:
 
-  - `--help`\
+  - [`--help`]{#opt-help}\
     Prints out a summary of the command syntax and exits.
 
-  - `--version`\
+  - [`--version`]{#opt-version}\
     Prints out the Nix version number on standard output and exits.
 
-  - `--verbose` / `-v`\
+  - [`--verbose`]{#opt-verbose} / `-v`\
     Increases the level of verbosity of diagnostic messages printed on
     standard error. For each Nix operation, the information printed on
     standard output is well-defined; any diagnostic information is
@@ -37,14 +37,14 @@ Most Nix commands accept the following command-line options:
       - 5\
         “Vomit”: print vast amounts of debug information.
 
-  - `--quiet`\
+  - [`--quiet`]{#opt-quiet}\
     Decreases the level of verbosity of diagnostic messages printed on
     standard error. This is the inverse option to `-v` / `--verbose`.
 
     This option may be specified repeatedly. See the previous verbosity
     levels list.
 
-  - `--log-format` *format*\
+  - [`--log-format`]{#opt-log-format} *format*\
     This option can be used to change the output of the log format, with
     *format* being one of:
 
@@ -66,14 +66,14 @@ Most Nix commands accept the following command-line options:
       - bar-with-logs\
         Display the raw logs, with the progress bar at the bottom.
 
-  - `--no-build-output` / `-Q`\
+  - [`--no-build-output`]{#opt-no-build-output} / `-Q`\
     By default, output written by builders to standard output and
     standard error is echoed to the Nix command's standard error. This
     option suppresses this behaviour. Note that the builder's standard
     output and error are always written to a log file in
     `prefix/nix/var/log/nix`.
 
-  - `--max-jobs` / `-j` *number*\
+  - [`--max-jobs`]{#opt-max-jobs} / `-j` *number*\
     Sets the maximum number of build jobs that Nix will perform in
     parallel to the specified number. Specify `auto` to use the number
     of CPUs in the system. The default is specified by the `max-jobs`
@@ -83,7 +83,7 @@ Most Nix commands accept the following command-line options:
     Setting it to `0` disallows building on the local machine, which is
     useful when you want builds to happen only on remote builders.
 
-  - `--cores`\
+  - [`--cores`]{#opt-cores}\
     Sets the value of the `NIX_BUILD_CORES` environment variable in
     the invocation of builders. Builders can use this variable at
     their discretion to control the maximum amount of parallelism. For
@@ -94,18 +94,18 @@ Most Nix commands accept the following command-line options:
     means that the builder should use all available CPU cores in the
     system.
 
-  - `--max-silent-time`\
+  - [`--max-silent-time`]{#opt-max-silent-time}\
     Sets the maximum number of seconds that a builder can go without
     producing any data on standard output or standard error. The
     default is specified by the `max-silent-time` configuration
     setting. `0` means no time-out.
 
-  - `--timeout`\
+  - [`--timeout`]{#opt-timeout}\
     Sets the maximum number of seconds that a builder can run. The
     default is specified by the `timeout` configuration setting. `0`
     means no timeout.
 
-  - `--keep-going` / `-k`\
+  - [`--keep-going`]{#opt-keep-going} / `-k`\
     Keep going in case of failed builds, to the greatest extent
     possible. That is, if building an input of some derivation fails,
     Nix will still build the other inputs, but not the derivation
@@ -113,13 +113,13 @@ Most Nix commands accept the following command-line options:
     for builds of substitutes), possibly killing builds in progress (in
     case of parallel or distributed builds).
 
-  - `--keep-failed` / `-K`\
+  - [`--keep-failed`]{#opt-keep-failed} / `-K`\
     Specifies that in case of a build failure, the temporary directory
     (usually in `/tmp`) in which the build takes place should not be
     deleted. The path of the build directory is printed as an
     informational message.
 
-  - `--fallback`\
+  - [`--fallback`]{#opt-fallback}\
     Whenever Nix attempts to build a derivation for which substitutes
     are known for each output path, but realising the output paths
     through the substitutes fails, fall back on building the derivation.
@@ -134,18 +134,18 @@ Most Nix commands accept the following command-line options:
     failure in obtaining the substitutes to lead to a full build from
     source (with the related consumption of resources).
 
-  - `--readonly-mode`\
+  - [`--readonly-mode`]{#opt-readonly-mode}\
     When this option is used, no attempt is made to open the Nix
     database. Most Nix operations do need database access, so those
     operations will fail.
 
-  - `--arg` *name* *value*\
+  - [`--arg`]{#opt-arg} *name* *value*\
     This option is accepted by `nix-env`, `nix-instantiate`,
     `nix-shell` and `nix-build`. When evaluating Nix expressions, the
     expression evaluator will automatically try to call functions that
     it encounters. It can automatically call functions for which every
     argument has a [default
-    value](../expressions/language-constructs.md#functions) (e.g.,
+    value](../language/constructs.md#functions) (e.g.,
     `{ argName ?  defaultValue }: ...`). With `--arg`, you can also
     call functions that have arguments without a default value (or
     override a default value). That is, if the evaluator encounters a
@@ -164,19 +164,19 @@ Most Nix commands accept the following command-line options:
 
     So if you call this Nix expression (e.g., when you do `nix-env -iA
     pkgname`), the function will be called automatically using the
-    value [`builtins.currentSystem`](../expressions/builtins.md) for
+    value [`builtins.currentSystem`](../language/builtins.md) for
     the `system` argument. You can override this using `--arg`, e.g.,
     `nix-env -iA pkgname --arg system \"i686-freebsd\"`. (Note that
     since the argument is a Nix string literal, you have to escape the
     quotes.)
 
-  - `--argstr` *name* *value*\
+  - [`--argstr`]{#opt-argstr} *name* *value*\
     This option is like `--arg`, only the value is not a Nix
     expression but a string. So instead of `--arg system
     \"i686-linux\"` (the outer quotes are to keep the shell happy) you
     can say `--argstr system i686-linux`.
 
-  - `--attr` / `-A` *attrPath*\
+  - [`--attr`]{#opt-attr} / `-A` *attrPath*\
     Select an attribute from the top-level Nix expression being
     evaluated. (`nix-env`, `nix-instantiate`, `nix-build` and
     `nix-shell` only.) The *attribute path* *attrPath* is a sequence
@@ -191,7 +191,7 @@ Most Nix commands accept the following command-line options:
     attribute of the fourth element of the array in the `foo` attribute
     of the top-level expression.
 
-  - `--expr` / `-E`\
+  - [`--expr`]{#opt-expr} / `-E`\
     Interpret the command line arguments as a list of Nix expressions to
     be parsed and evaluated, rather than as a list of file names of Nix
     expressions. (`nix-instantiate`, `nix-build` and `nix-shell` only.)
@@ -202,17 +202,17 @@ Most Nix commands accept the following command-line options:
     use, give your expression to the `nix-shell -p` convenience flag
     instead.
 
-  - `-I` *path*\
+  - [`-I`]{#opt-I} *path*\
     Add a path to the Nix expression search path. This option may be
     given multiple times. See the `NIX_PATH` environment variable for
     information on the semantics of the Nix search path. Paths added
     through `-I` take precedence over `NIX_PATH`.
 
-  - `--option` *name* *value*\
+  - [`--option`]{#opt-option} *name* *value*\
     Set the Nix configuration option *name* to *value*. This overrides
     settings in the Nix configuration file (see nix.conf5).
 
-  - `--repair`\
+  - [`--repair`]{#opt-repair}\
     Fix corrupted or missing store paths by redownloading or rebuilding
     them. Note that this is slow because it requires computing a
     cryptographic hash of the contents of every path in the closure of