diff --git a/libexec/rbenv---version b/libexec/rbenv---version
index c1313e45..222ad004 100755
--- a/libexec/rbenv---version
+++ b/libexec/rbenv---version
@@ -1,11 +1,11 @@
 #!/usr/bin/env bash
 # Summary: Display the version of rbenv
 #
-# Displays the current revision info of rbenv from git if available,
-# or falls back to the version of the last release.
+# Displays the version number of this rbenv release, including the
+# current revision from git, if available.
 #
 # The format of the git revision is:
-#   ${version}-${num_commits}-g${git_sha}
+#   <version>-<num_commits>-<git_sha>
 # where `num_commits` is the number of commits since `version` was
 # tagged.
 
diff --git a/libexec/rbenv-completions b/libexec/rbenv-completions
index d5cbac32..2cc14e67 100755
--- a/libexec/rbenv-completions
+++ b/libexec/rbenv-completions
@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-# Usage: rbenv completions COMMAND [arg1 arg2...]
+# Usage: rbenv completions <command> [arg1 arg2...]
 
 set -e
 [ -n "$RBENV_DEBUG" ] && set -x
diff --git a/libexec/rbenv-exec b/libexec/rbenv-exec
index 60880704..45dbbf80 100755
--- a/libexec/rbenv-exec
+++ b/libexec/rbenv-exec
@@ -1,17 +1,17 @@
 #!/usr/bin/env bash
 #
-# Summary: Run an executable with the right Ruby version
+# Summary: Run an executable with the selected Ruby version
 #
-# Usage: rbenv exec COMMAND [arg1 arg2...]
+# Usage: rbenv exec <command> [arg1 arg2...]
 #
 # Runs an executable by first preparing PATH so that the selected Ruby
-# version is prepended to it.
+# version's `bin' directory is at the front.
 #
-# For example, doing:
-#   RBENV_VERSION=1.9.3-p327 rbenv exec bundle install
+# For example, if the currently selected Ruby version is 1.9.3-p327:
+#   rbenv exec bundle install
 #
-# has an effect is if this was done:
-#   PATH=~/.rbenv/versions/1.9.3-p327:"$PATH" bundle install
+# is equivalent to:
+#   PATH="$RBENV_ROOT/versions/1.9.3-p327/bin:$PATH" bundle install
 
 set -e
 [ -n "$RBENV_DEBUG" ] && set -x
diff --git a/libexec/rbenv-help b/libexec/rbenv-help
index 0c39b696..e42a123a 100755
--- a/libexec/rbenv-help
+++ b/libexec/rbenv-help
@@ -7,10 +7,10 @@
 # Parses and displays help contents from a command's source file.
 #
 # A command is considered documented if it starts with a comment block
-# that has at least one of the following sections: `Summary' and
-# `Usage'. Usage instructions can span multiple lines as long as
-# subsequent lines are indented.  Everything else in the comment is
-# considered to be regular help contents.
+# that has a `Summary:' or `Usage:' section. Usage instructions can
+# span multiple lines as long as subsequent lines are indented.
+# The remainder of the comment block is displayed as extended
+# documentation.
 
 set -e
 [ -n "$RBENV_DEBUG" ] && set -x
diff --git a/libexec/rbenv-init b/libexec/rbenv-init
index 6d53a23e..0ae9cf47 100755
--- a/libexec/rbenv-init
+++ b/libexec/rbenv-init
@@ -1,7 +1,6 @@
 #!/usr/bin/env bash
-# Summary: Configure shell environment for rbenv
-# Usage: rbenv init [SHELL]
-#        rbenv init - [--no-rehash] [SHELL]
+# Summary: Configure the shell environment for rbenv
+# Usage: eval "$(rbenv init - [--no-rehash] [<shell>])"
 
 set -e
 [ -n "$RBENV_DEBUG" ] && set -x
diff --git a/libexec/rbenv-prefix b/libexec/rbenv-prefix
index 0b16fd9e..a0aebab2 100755
--- a/libexec/rbenv-prefix
+++ b/libexec/rbenv-prefix
@@ -3,7 +3,8 @@
 # Usage: rbenv prefix [<version>]
 #
 # Displays the directory where a Ruby version is installed. If no
-# version is given, it uses the currently selected version.
+# version is given, `rbenv prefix' displays the location of the
+# currently selected version.
 
 set -e
 [ -n "$RBENV_DEBUG" ] && set -x
diff --git a/libexec/rbenv-rehash b/libexec/rbenv-rehash
index a50819dd..aa924efe 100755
--- a/libexec/rbenv-rehash
+++ b/libexec/rbenv-rehash
@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-# Summary: Rehash rbenv shims (run this after installing binaries)
+# Summary: Rehash rbenv shims (run this after installing executables)
 
 set -e
 [ -n "$RBENV_DEBUG" ] && set -x
diff --git a/libexec/rbenv-root b/libexec/rbenv-root
index e632d9d1..64fc90b8 100755
--- a/libexec/rbenv-root
+++ b/libexec/rbenv-root
@@ -1,3 +1,3 @@
 #!/usr/bin/env bash
-# Summary: Display rbenv directory where versions and shims are kept
+# Summary: Display the root directory where versions and shims are kept
 echo $RBENV_ROOT
diff --git a/libexec/rbenv-version b/libexec/rbenv-version
index 40d15392..d1fefcc5 100755
--- a/libexec/rbenv-version
+++ b/libexec/rbenv-version
@@ -1,8 +1,9 @@
 #!/usr/bin/env bash
 # Summary: Show the current Ruby version and its origin
 #
-# Shows the current Ruby version and where it's set from. To obtain
-# only the version string, use `rbenv version-name'.
+# Shows the currently selected Ruby version and how it was
+# selected. To obtain only the version string, use `rbenv
+# version-name'.
 
 set -e
 [ -n "$RBENV_DEBUG" ] && set -x
diff --git a/libexec/rbenv-version-file-read b/libexec/rbenv-version-file-read
index 518bc477..69ec78b9 100755
--- a/libexec/rbenv-version-file-read
+++ b/libexec/rbenv-version-file-read
@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-# Usage: rbenv version-file-read FILE
+# Usage: rbenv version-file-read <file>
 set -e
 [ -n "$RBENV_DEBUG" ] && set -x
 
diff --git a/libexec/rbenv-version-file-write b/libexec/rbenv-version-file-write
index da6a1c9a..04a0febb 100755
--- a/libexec/rbenv-version-file-write
+++ b/libexec/rbenv-version-file-write
@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-# Usage: rbenv version-file-write FILENAME VERSION
+# Usage: rbenv version-file-write <file> <version>
 
 set -e
 [ -n "$RBENV_DEBUG" ] && set -x
diff --git a/libexec/rbenv-version-origin b/libexec/rbenv-version-origin
index ceef0f9d..ae7abf9c 100755
--- a/libexec/rbenv-version-origin
+++ b/libexec/rbenv-version-origin
@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-# Summary: Show where the current Ruby version is set from
+# Summary: Explain how the current Ruby version is set
 set -e
 [ -n "$RBENV_DEBUG" ] && set -x