diff --git a/Library/Homebrew/cmd/list.rb b/Library/Homebrew/cmd/list.rb
index 40f5875f9f..e232eb79ba 100644
--- a/Library/Homebrew/cmd/list.rb
+++ b/Library/Homebrew/cmd/list.rb
@@ -34,9 +34,9 @@ module Homebrew
              description: "Show the versions of pinned formulae, or only the specified (pinned) "\
                           "formulae if <formula> are provided. See also `pin`, `unpin`."
       switch "--formula", "--formulae",
-             description: "List only formulae."
+             description: "List only formulae. `This is the default action on non TTY.`"
       switch "--cask", "--casks",
-             description: "List only casks."
+             description: "List only casks, or <cask> if provided."
       # passed through to ls
       switch "-1",
              description: "Force output to be one entry per line. " \
@@ -87,7 +87,13 @@ module Homebrew
         ls_args << "-r" if args.r?
         ls_args << "-t" if args.t?
 
-        safe_system "ls", *ls_args, HOMEBREW_CELLAR
+        if !$stdout.tty? && !args.formula?
+          odeprecated "`brew list` to only list formulae", "`brew list --formula`"
+          safe_system "ls", *ls_args, HOMEBREW_CELLAR
+        else
+          safe_system "ls", *ls_args, HOMEBREW_CELLAR
+          list_casks(args: args) unless args.formula?
+        end
       end
     elsif args.verbose? || !$stdout.tty?
       system_command! "find", args: args.named.to_kegs.map(&:to_s) + %w[-not -type d -print], print_stdout: true
diff --git a/Library/Homebrew/test/cmd/list_spec.rb b/Library/Homebrew/test/cmd/list_spec.rb
index ff438b222b..a06fa06156 100644
--- a/Library/Homebrew/test/cmd/list_spec.rb
+++ b/Library/Homebrew/test/cmd/list_spec.rb
@@ -15,7 +15,7 @@ describe "brew list", :integration_test do
       (HOMEBREW_CELLAR/f/"1.0/somedir").mkpath
     end
 
-    expect { brew "list" }
+    expect { brew "list", "--formula" }
       .to output("#{formulae.join("\n")}\n").to_stdout
       .and not_to_output.to_stderr
       .and be_a_success
diff --git a/completions/zsh/_brew b/completions/zsh/_brew
index e0f635b248..1ff67fac63 100644
--- a/completions/zsh/_brew
+++ b/completions/zsh/_brew
@@ -62,10 +62,17 @@ __brew_formulae() {
 
 __brew_installed_formulae() {
   local -a formulae
-  formulae=($(brew list))
+  formulae=($(brew list --formula))
   _describe -t formulae 'installed formulae' formulae
 }
 
+__brew_installed_casks() {
+  local -a list
+  local expl
+  list=( $(brew list --cask) )
+  _wanted list expl 'installed casks' compadd -a list
+}
+
 __brew_outdated_formulae() {
   local -a formulae
   formulae=($(brew outdated))
@@ -493,11 +500,12 @@ _brew_linkage() {
 # brew list, ls [--full-name]:
 # brew list, ls --unbrewed:
 # brew list, ls [--versions [--multiple]] [--pinned] [formulae]:
-# brew list, ls --cask:
+# brew list, ls [--cask|--formula]:
 _brew_list() {
   local state
   _arguments \
     - formulae \
+      '--formula[list install formulae]' \
       '--full-name[print formulae with fully-qualified names]' \
       '--unbrewed[files in brew --prefix not controlled by brew]' \
       '--pinned[list all versions of pinned formulae]' \
@@ -575,7 +583,7 @@ _brew_outdated() {
       '--fetch-HEAD[detect if the HEAD installation of the formula is outdated]' \
     - cask \
       '--cask[list outdated Casks]' \
-      '--greedy[also list Casks with auto_updates or version \:latest]' \
+      '--greedy[also list Casks with auto_updates or version \:latest]'
 }
 
 # brew pin formulae:
diff --git a/docs/Manpage.md b/docs/Manpage.md
index 5f2770b4a5..3bd3c032d9 100644
--- a/docs/Manpage.md
+++ b/docs/Manpage.md
@@ -364,9 +364,9 @@ If *`formula`* is provided, summarise the paths within its current keg.
 * `--pinned`:
   Show the versions of pinned formulae, or only the specified (pinned) formulae if *`formula`* are provided. See also `pin`, `unpin`.
 * `--formula`:
-  List only formulae.
+  List only formulae. `This is the default action on non TTY.`
 * `--cask`:
-  List only casks.
+  List only casks, or *`cask`* if provided.
 * `-1`:
   Force output to be one entry per line. This is the default when output is not to a terminal.
 * `-l`:
diff --git a/manpages/brew.1 b/manpages/brew.1
index d19a2c0a58..24b3607aab 100644
--- a/manpages/brew.1
+++ b/manpages/brew.1
@@ -533,11 +533,11 @@ Show the versions of pinned formulae, or only the specified (pinned) formulae if
 .
 .TP
 \fB\-\-formula\fR
-List only formulae\.
+List only formulae\. \fBThis is the default action on non TTY\.\fR
 .
 .TP
 \fB\-\-cask\fR
-List only casks\.
+List only casks, or \fIcask\fR if provided\.
 .
 .TP
 \fB\-1\fR