From ad851706ab434abf1cccd94955d919747f86a987 Mon Sep 17 00:00:00 2001
From: Tim Ledbetter <timledbetter@gmail.com>
Date: Tue, 30 May 2023 17:51:18 +0100
Subject: [PATCH] pgrep: Add `-c` option to show the number of matches

---
 Base/usr/share/man/man1/pgrep.md |  3 ++-
 Userland/Utilities/pgrep.cpp     | 27 ++++++++++++++++-----------
 2 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/Base/usr/share/man/man1/pgrep.md b/Base/usr/share/man/man1/pgrep.md
index 235d90045b..23a8d41403 100644
--- a/Base/usr/share/man/man1/pgrep.md
+++ b/Base/usr/share/man/man1/pgrep.md
@@ -5,11 +5,12 @@ pgrep - look up processes based on name
 ## Synopsis
 
 ```sh
-$ pgrep [-d delimiter] [--ignore-case] [--invert-match] <process-name>
+$ pgrep [--count] [-d delimiter] [--ignore-case] [--invert-match] <process-name>
 ```
 
 ## Options
 
+* `-c`, `--count`: Suppress normal output and print the number of matching processes
 * `-d`, `--delimiter`: Set the string used to delimit multiple pids
 * `-i`, `--ignore-case`: Make matches case-insensitive
 * `-v`, `--invert-match`: Select non-matching lines
diff --git a/Userland/Utilities/pgrep.cpp b/Userland/Utilities/pgrep.cpp
index 4c7fa0b29c..5cc16839dc 100644
--- a/Userland/Utilities/pgrep.cpp
+++ b/Userland/Utilities/pgrep.cpp
@@ -20,12 +20,14 @@ ErrorOr<int> serenity_main(Main::Arguments args)
     TRY(Core::System::unveil("/etc/passwd", "r"));
     TRY(Core::System::unveil(nullptr, nullptr));
 
+    bool display_number_of_matches = false;
     auto pid_delimiter = "\n"sv;
     bool case_insensitive = false;
     bool invert_match = false;
     StringView pattern;
 
     Core::ArgsParser args_parser;
+    args_parser.add_option(display_number_of_matches, "Suppress normal output and print the number of matching processes", "count", 'c');
     args_parser.add_option(pid_delimiter, "Set the string used to delimit multiple pids", "delimiter", 'd', nullptr);
     args_parser.add_option(case_insensitive, "Make matches case-insensitive", "ignore-case", 'i');
     args_parser.add_option(invert_match, "Select non-matching lines", "invert-match", 'v');
@@ -51,20 +53,23 @@ ErrorOr<int> serenity_main(Main::Arguments args)
         }
     }
 
-    quick_sort(matches);
+    if (display_number_of_matches) {
+        outln("{}", matches.size());
+    } else {
+        quick_sort(matches);
+        auto displayed_at_least_one = false;
+        for (auto& match : matches) {
+            if (displayed_at_least_one)
+                out("{}{}"sv, pid_delimiter, match);
+            else
+                out("{}"sv, match);
+
+            displayed_at_least_one = true;
+        }
 
-    auto displayed_at_least_one = false;
-    for (auto& match : matches) {
         if (displayed_at_least_one)
-            out("{}{}"sv, pid_delimiter, match);
-        else
-            out("{}"sv, match);
-
-        displayed_at_least_one = true;
+            outln();
     }
 
-    if (displayed_at_least_one)
-        outln();
-
     return matches.size() > 0 ? 0 : 1;
 }