3 files changed, 14 insertions, 2 deletions
diff --git a/doc/manual/src/command-ref/nix-build.md b/doc/manual/src/command-ref/nix-build.md
index aacb32a25..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
diff --git a/doc/manual/src/command-ref/nix-env.md b/doc/manual/src/command-ref/nix-env.md
index 8d6abaf52..a372c5eae 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:
@@ -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-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