cmd/shellenv: use Bash.

This speeds up execution by 3x on my machine and the script is simple
enough to warrant this.

Library/Homebrew/cmd/shellenv.rb

@@ -1,16 +0,0 @@
-#:  * `shellenv`:
-#:    Prints export statements - run them in a shell and this installation of
-#:    Homebrew will be included into your PATH, MANPATH, and INFOPATH.
-#:    Tip: have your dotfiles eval the output of this command
-
-module Homebrew
-  module_function
-
-  def shellenv
-    puts <<~EOS
-      export PATH="#{HOMEBREW_PREFIX}/bin:#{HOMEBREW_PREFIX}/sbin:$PATH"
-      export MANPATH="#{HOMEBREW_PREFIX}/share/man:$MANPATH"
-      export INFOPATH="#{HOMEBREW_PREFIX}/share/info:$INFOPATH"
-    EOS
-  end
-end

Library/Homebrew/cmd/shellenv.sh

@@ -0,0 +1,18 @@
+#:  * `shellenv`:
+#:    Prints export statements - run them in a shell and this installation of
+#:    Homebrew will be included into your PATH, MANPATH, and INFOPATH.
+#:
+#:    HOMEBREW_PREFIX, HOMEBREW_CELLAR and HOMEBREW_REPOSITORY are also exported
+#:    to save multiple queries of those variables.
+#:
+#:    Consider adding evaluating the output in your dotfiles (e.g. `~/.profile`)
+#:    with `eval $(brew shellenv)`
+
+homebrew-shellenv() {
+  echo "export HOMEBREW_PREFIX=\"$HOMEBREW_PREFIX\""
+  echo "export HOMEBREW_CELLAR=\"$HOMEBREW_CELLAR\""
+  echo "export HOMEBREW_REPOSITORY=\"$HOMEBREW_REPOSITORY\""
+  echo "export PATH=\"$HOMEBREW_PREFIX/bin:$HOMEBREW_PREFIX/sbin:\$PATH\""
+  echo "export MANPATH=\"$HOMEBREW_PREFIX/share/man:\$MANPATH\""
+  echo "export INFOPATH=\"$HOMEBREW_PREFIX/share/info:\$INFOPATH\""
+}

Library/Homebrew/test/cmd/shellenv_spec.rb

@@ -1,8 +0,0 @@
-describe "brew shellenv", :integration_test do
-  it "doesn't fail" do
-    expect { brew "shellenv" }
-      .to output(%r{#{HOMEBREW_PREFIX}/bin}).to_stdout
-      .and not_to_output.to_stderr
-      .and be_a_success
-  end
-end

docs/Manpage.md

@@ -444,7 +444,12 @@ With `--verbose` or `-v`, many commands print extra debugging information. Note
   * `shellenv`:
     Prints export statements - run them in a shell and this installation of
     Homebrew will be included into your PATH, MANPATH, and INFOPATH.
-    Tip: have your dotfiles eval the output of this command
+
+    HOMEBREW_PREFIX, HOMEBREW_CELLAR and HOMEBREW_REPOSITORY are also exported
+    to save multiple queries of those variables.
+
+    Consider adding evaluating the output in your dotfiles (e.g. `~/.profile`)
+    with `eval $(brew shellenv)`
 
   * `style` [`--fix`] [`--display-cop-names`] [`--only-cops=``cops`|`--except-cops=``cops`] [`files`|`taps`|`formulae`]:
     Check formulae or files for conformance to Homebrew style guidelines.

manpages/brew.1

@@ -404,7 +404,13 @@ If \fB\-\-desc\fR is passed, search formulae with a description matching \fItext
 If \fB\-\-env=std\fR is passed, use the standard \fBPATH\fR instead of superenv\'s\.
 .
 .IP "\(bu" 4
-\fBshellenv\fR: Prints export statements \- run them in a shell and this installation of Homebrew will be included into your PATH, MANPATH, and INFOPATH\. Tip: have your dotfiles eval the output of this command
+\fBshellenv\fR: Prints export statements \- run them in a shell and this installation of Homebrew will be included into your PATH, MANPATH, and INFOPATH\.
+.
+.IP
+HOMEBREW_PREFIX, HOMEBREW_CELLAR and HOMEBREW_REPOSITORY are also exported to save multiple queries of those variables\.
+.
+.IP
+Consider adding evaluating the output in your dotfiles (e\.g\. \fB~/\.profile\fR) with \fBeval $(brew shellenv)\fR
 .
 .IP "\(bu" 4
 \fBstyle\fR [\fB\-\-fix\fR] [\fB\-\-display\-cop\-names\fR] [\fB\-\-only\-cops=\fR\fIcops\fR|\fB\-\-except\-cops=\fR\fIcops\fR] [\fIfiles\fR|\fItaps\fR|\fIformulae\fR]: Check formulae or files for conformance to Homebrew style guidelines\.