From 302b8a7b1b075c48f219b1fa1ea6cedb7a1d4bc0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E6=9D=8E=E9=80=9A=E6=B4=B2?= <zhangsongcui3371@sina.com>
Date: Wed, 5 Nov 2025 10:00:31 +0800
Subject: [PATCH] CommandLine: adds dynamic output refresh support with
 interval option

---
 src/common/init.c  | 13 ++++++++++---
 src/data/help.json |  9 +++++++++
 src/fastfetch.c    | 33 +++++++++++++++++++++++++++++----
 src/fastfetch.h    |  1 +
 src/flashfetch.c   |  2 ++
 src/logo/logo.c    |  3 +++
 6 files changed, 54 insertions(+), 7 deletions(-)

diff --git a/src/common/init.c b/src/common/init.c
index 9735c96ed..8e27ebaf1 100644
--- a/src/common/init.c
+++ b/src/common/init.c
@@ -30,6 +30,7 @@ static void initState(FFstate* state)
     ffPlatformInit(&state->platform);
     state->configDoc = NULL;
     state->resultDoc = NULL;
+    state->dynamicInterval = 0;
 
     {
         // don't enable bright color if the terminal is in light mode
@@ -74,6 +75,9 @@ static void resetConsole(void)
     #if defined(_WIN32)
         fflush(stdout);
     #endif
+
+    if(instance.state.dynamicInterval > 0)
+        fputs("\033[?1049l", stdout); // Disable alternate buffer
 }
 
 #ifdef _WIN32
@@ -130,14 +134,17 @@ void ffStart(void)
     if(ffDisableLinewrap)
         fputs("\033[?7l", stdout);
 
+    if(instance.state.dynamicInterval > 0)
+    {
+        fputs("\033[?1049h\033[H", stdout); // Enable alternate buffer
+        fflush(stdout);
+    }
+
     ffLogoPrint();
 }
 
 void ffFinish(void)
 {
-    if(instance.config.logo.printRemaining)
-        ffLogoPrintRemaining();
-
     resetConsole();
 }
 
diff --git a/src/data/help.json b/src/data/help.json
index 745570ff2..df10972cc 100644
--- a/src/data/help.json
+++ b/src/data/help.json
@@ -74,6 +74,15 @@
             },
             "desc": "Enable or disable JSON output",
             "remark": "Shortcut for `--format json`"
+        },
+        {
+            "long": "dynamic-interval",
+            "desc": "Keep fastfetch open and update the output every <num> milliseconds",
+            "remark": "0 (default) to disable the behavior; don't work with --json",
+            "arg": {
+                "type": "num",
+                "default": 0
+            }
         }
     ],
     "Config": [
diff --git a/src/fastfetch.c b/src/fastfetch.c
index b3845246e..6a742a5e7 100644
--- a/src/fastfetch.c
+++ b/src/fastfetch.c
@@ -3,6 +3,7 @@
 #include "common/init.h"
 #include "common/io/io.h"
 #include "common/jsonconfig.h"
+#include "common/time.h"
 #include "detection/version/version.h"
 #include "logo/logo.h"
 #include "util/stringUtils.h"
@@ -670,6 +671,8 @@ static void parseCommand(FFdata* data, char* key, char* value)
             {},
         }));
     }
+    else if(ffStrEqualsIgnCase(key, "--dynamic-interval"))
+        instance.state.dynamicInterval = ffOptionParseUInt32(key, value); // seconds to milliseconds
     else
         return;
 
@@ -768,15 +771,31 @@ static void run(FFdata* data)
         if (!instance.config.display.noBuffer) fflush(stdout);
     #endif
 
-    if (useJsonConfig)
-        ffPrintJsonConfig(false, instance.state.resultDoc);
-    else
-        ffPrintCommandOption(data, instance.state.resultDoc);
+    while (true)
+    {
+        if (useJsonConfig)
+            ffPrintJsonConfig(false, instance.state.resultDoc);
+        else
+            ffPrintCommandOption(data, instance.state.resultDoc);
+
+        if (instance.state.dynamicInterval > 0)
+        {
+            fflush(stdout);
+            ffTimeSleep(instance.state.dynamicInterval);
+            fputs("\e[H", stdout);
+        }
+        else
+            break;
+    }
 
     if (instance.state.resultDoc)
         yyjson_mut_write_fp(stdout, instance.state.resultDoc, YYJSON_WRITE_INF_AND_NAN_AS_NULL | YYJSON_WRITE_PRETTY_TWO_SPACES | YYJSON_WRITE_NEWLINE_AT_END, NULL, NULL);
     else
+    {
+        if (instance.config.logo.printRemaining)
+            ffLogoPrintRemaining();
         ffFinish();
+    }
 }
 
 static void writeConfigFile(FFdata* data)
@@ -835,6 +854,12 @@ int main(int argc, char** argv)
     };
 
     parseArguments(&data, argc, argv, parseCommand);
+    if(instance.state.dynamicInterval && instance.state.resultDoc)
+    {
+        fprintf(stderr, "Error: --dynamic-interval cannot be used with --json\n");
+        exit(400);
+    }
+
     if(!data.configLoaded && !getenv("NO_CONFIG"))
         parseConfigFiles();
     parseArguments(&data, argc, argv, (void*) parseOption);
diff --git a/src/fastfetch.h b/src/fastfetch.h
index f38bb864d..bb5197d6c 100644
--- a/src/fastfetch.h
+++ b/src/fastfetch.h
@@ -46,6 +46,7 @@ typedef struct FFstate
     yyjson_mut_doc* resultDoc;
     FFstrbuf genConfigPath;
     bool fullConfig;
+    uint32_t dynamicInterval;
 } FFstate;
 
 typedef struct FFinstance
diff --git a/src/flashfetch.c b/src/flashfetch.c
index f4256cff6..e4815686c 100644
--- a/src/flashfetch.c
+++ b/src/flashfetch.c
@@ -1,6 +1,7 @@
 #include "fastfetch.h"
 
 #include "common/init.h"
+#include "logo/logo.h"
 #include "modules/modules.h"
 
 // A dirty replicate of neofetch
@@ -136,6 +137,7 @@ int main(void)
         ffPrintColors(&options);
     }
 
+    ffLogoPrintRemaining();
     ffFinish();
     ffDestroyInstance();
     return 0;
diff --git a/src/logo/logo.c b/src/logo/logo.c
index 3081dc2c4..02ff36c9c 100644
--- a/src/logo/logo.c
+++ b/src/logo/logo.c
@@ -728,6 +728,9 @@ void ffLogoPrintLine(void)
     if(instance.state.logoWidth > 0)
         printf("\033[%uC", instance.state.logoWidth);
 
+    if (instance.state.dynamicInterval > 0)
+        fputs("\033[K", stdout);
+
     ++instance.state.keysHeight;
 }