diff --git a/ios_system.xcodeproj/project.pbxproj b/ios_system.xcodeproj/project.pbxproj
index f4048bff..78462f6e 100644
--- a/ios_system.xcodeproj/project.pbxproj
+++ b/ios_system.xcodeproj/project.pbxproj
@@ -56,6 +56,7 @@
 		224AAC5C21CB931300F8C22F /* reallocarray.c in Sources */ = {isa = PBXBuildFile; fileRef = 224AAC5B21CB931300F8C22F /* reallocarray.c */; };
 		224AAC5E21CB935100F8C22F /* utf8.c in Sources */ = {isa = PBXBuildFile; fileRef = 224AAC5D21CB935100F8C22F /* utf8.c */; };
 		224AAC6021CB93AE00F8C22F /* readpass.c in Sources */ = {isa = PBXBuildFile; fileRef = 224AAC5F21CB93AE00F8C22F /* readpass.c */; settings = {COMPILER_FLAGS = "-x objective-c"; }; };
+		224B48F4279491FE00D310A8 /* source.swift in Sources */ = {isa = PBXBuildFile; fileRef = 224B48F3279491FE00D310A8 /* source.swift */; };
 		225782911FDB4D390050F312 /* curl_config.h in Headers */ = {isa = PBXBuildFile; fileRef = 2257811A1FDB4D380050F312 /* curl_config.h */; };
 		225E1B6F2067F39F005AC151 /* tar.h in Headers */ = {isa = PBXBuildFile; fileRef = 225E1B6D2067F39F005AC151 /* tar.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		225F06102016751900466685 /* getopt_long.c in Sources */ = {isa = PBXBuildFile; fileRef = 225F060F2016751800466685 /* getopt_long.c */; };
@@ -626,6 +627,7 @@
 		224AAC5B21CB931300F8C22F /* reallocarray.c */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.c; name = reallocarray.c; path = "ssh_keygen/openbsd-compat/reallocarray.c"; sourceTree = "<group>"; };
 		224AAC5D21CB935100F8C22F /* utf8.c */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.c; name = utf8.c; path = ssh_keygen/utf8.c; sourceTree = "<group>"; };
 		224AAC5F21CB93AE00F8C22F /* readpass.c */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.c; name = readpass.c; path = ssh_keygen/readpass.c; sourceTree = "<group>"; };
+		224B48F3279491FE00D310A8 /* source.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = source.swift; sourceTree = "<group>"; };
 		2253BA1D201942B10019CB39 /* libresolv.9.tbd */ = {isa = PBXFileReference; lastKnownFileType = "sourcecode.text-based-dylib-definition"; name = libresolv.9.tbd; path = usr/lib/libresolv.9.tbd; sourceTree = SDKROOT; };
 		22577D451FDB47A90050F312 /* err.c */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.c; path = err.c; sourceTree = "<group>"; };
 		22577D461FDB47A90050F312 /* lafe_err.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = lafe_err.h; sourceTree = "<group>"; };
@@ -1941,6 +1943,7 @@
 				22F0803620973712003C3BF0 /* sleep.c */,
 				221CD98D21E8B03D00F3B47C /* open.m */,
 				22484B022434C5BB00D6BDDA /* jsc.swift */,
+				224B48F3279491FE00D310A8 /* source.swift */,
 				222CC4D9218CBEED00D3A11C /* xarg */,
 				22C5057C209875E200FDDFA9 /* find */,
 				225F060920163BFC00466685 /* tee */,
@@ -2622,6 +2625,7 @@
 					};
 					22F6A10B2068390800E618F9 = {
 						CreatedOnToolsVersion = 9.3;
+						LastSwiftMigration = 1320;
 						ProvisioningStyle = Automatic;
 					};
 					22F6A127206839EF00E618F9 = {
@@ -2935,6 +2939,7 @@
 				22C5058C2098ADD800FDDFA9 /* main.c in Sources */,
 				22F6A1202068395B00E618F9 /* proc_compare.c in Sources */,
 				22F6A11B2068394E00E618F9 /* printenv.c in Sources */,
+				224B48F4279491FE00D310A8 /* source.swift in Sources */,
 				22F6A1152068393E00E618F9 /* echo.c in Sources */,
 				22F6A11C2068395200E618F9 /* pwd.c in Sources */,
 				22C505862098ADD800FDDFA9 /* find.c in Sources */,
@@ -3647,6 +3652,8 @@
 		22F6A1122068390800E618F9 /* Debug */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				BUILD_LIBRARY_FOR_DISTRIBUTION = YES;
+				CLANG_ENABLE_MODULES = YES;
 				CLANG_ENABLE_OBJC_WEAK = YES;
 				CLANG_WARN_DEPRECATED_OBJC_IMPLEMENTATIONS = YES;
 				CLANG_WARN_OBJC_IMPLICIT_RETAIN_SELF = YES;
@@ -3670,6 +3677,7 @@
 				PRODUCT_NAME = "$(TARGET_NAME:c99extidentifier)";
 				SKIP_INSTALL = YES;
 				STRIP_SWIFT_SYMBOLS = NO;
+				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
 				SWIFT_VERSION = 5.0;
 			};
 			name = Debug;
@@ -3677,6 +3685,8 @@
 		22F6A1132068390800E618F9 /* Release */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				BUILD_LIBRARY_FOR_DISTRIBUTION = YES;
+				CLANG_ENABLE_MODULES = YES;
 				CLANG_ENABLE_OBJC_WEAK = YES;
 				CLANG_WARN_DEPRECATED_OBJC_IMPLEMENTATIONS = YES;
 				CLANG_WARN_OBJC_IMPLICIT_RETAIN_SELF = YES;
diff --git a/ios_system.xcodeproj/xcuserdata/holzschu.xcuserdatad/xcschemes/xcschememanagement.plist b/ios_system.xcodeproj/xcuserdata/holzschu.xcuserdatad/xcschemes/xcschememanagement.plist
index b4b693e1..425c485d 100644
--- a/ios_system.xcodeproj/xcuserdata/holzschu.xcuserdatad/xcschemes/xcschememanagement.plist
+++ b/ios_system.xcodeproj/xcuserdata/holzschu.xcuserdatad/xcschemes/xcschememanagement.plist
@@ -7,7 +7,7 @@
 		<key>awk.xcscheme_^#shared#^_</key>
 		<dict>
 			<key>orderHint</key>
-			<integer>3</integer>
+			<integer>0</integer>
 		</dict>
 		<key>curl_ios.xcscheme_^#shared#^_</key>
 		<dict>
@@ -17,17 +17,17 @@
 		<key>files.xcscheme_^#shared#^_</key>
 		<dict>
 			<key>orderHint</key>
-			<integer>6</integer>
+			<integer>4</integer>
 		</dict>
 		<key>ios_system.xcscheme_^#shared#^_</key>
 		<dict>
 			<key>orderHint</key>
-			<integer>1</integer>
+			<integer>2</integer>
 		</dict>
 		<key>shell.xcscheme_^#shared#^_</key>
 		<dict>
 			<key>orderHint</key>
-			<integer>0</integer>
+			<integer>3</integer>
 		</dict>
 		<key>ssh_cmd.xcscheme_^#shared#^_</key>
 		<dict>
@@ -37,12 +37,12 @@
 		<key>tar.xcscheme_^#shared#^_</key>
 		<dict>
 			<key>orderHint</key>
-			<integer>4</integer>
+			<integer>1</integer>
 		</dict>
 		<key>text.xcscheme_^#shared#^_</key>
 		<dict>
 			<key>orderHint</key>
-			<integer>2</integer>
+			<integer>6</integer>
 		</dict>
 	</dict>
 </dict>
diff --git a/ios_system/ios_system.h b/ios_system/ios_system.h
index 140fbc84..37c9b7ee 100644
--- a/ios_system/ios_system.h
+++ b/ios_system/ios_system.h
@@ -71,6 +71,9 @@ extern int ios_activePager(void);
 extern void ios_setContext(const void *context);
 extern void* ios_getContext(void);
 extern void ios_setDirectoryURL(NSURL* workingDirectoryURL);
+extern void newPreviousDirectory(void);
+extern void makeGlobal(void);
+extern void makeLocal(void);
 extern void replaceCommand(NSString* commandName, NSString* functionName, bool allOccurences);
 extern NSError* addCommandList(NSString* fileLocation);
 extern int numPythonInterpreters;
diff --git a/libc_replacement.c b/libc_replacement.c
index cc1372f8..faafe4fc 100644
--- a/libc_replacement.c
+++ b/libc_replacement.c
@@ -128,6 +128,7 @@ int ios_putw(int w, FILE *stream) {
 static pthread_t thread_ids[IOS_MAX_THREADS];
 static int numVariablesSet[IOS_MAX_THREADS];
 static char** environment[IOS_MAX_THREADS];
+static char** copyEnvironment[IOS_MAX_THREADS];
 static char previousDirectory[IOS_MAX_THREADS][MAXPATHLEN];
 static int previousPid[IOS_MAX_THREADS];
 
@@ -138,12 +139,22 @@ pthread_mutex_t pid_mtx = PTHREAD_MUTEX_INITIALIZER;
 _Atomic(int) cleanup_counter = 0;
 static pid_t last_allocated_pid = 0;
 
+
+void makeGlobal(void) {
+    copyEnvironment[current_pid] = environment[current_pid];
+    environment[current_pid] = NULL;
+}
+void makeLocal(void) {
+    environment[current_pid] = copyEnvironment[current_pid];
+    copyEnvironment[current_pid] = NULL;
+}
+
 inline pthread_t ios_getThreadId(pid_t pid) {
     // return ios_getLastThreadId(); // previous behaviour
     return thread_ids[pid];
 }
 
-void newPreviousDirectory() {
+void newPreviousDirectory(void) {
     // Called when a command calls "cd". Actually changes the directory for that command.
     getwd(previousDirectory[current_pid]);
 }
diff --git a/shell_cmds_ios/source.swift b/shell_cmds_ios/source.swift
new file mode 100644
index 00000000..b1d82534
--- /dev/null
+++ b/shell_cmds_ios/source.swift
@@ -0,0 +1,83 @@
+//
+//  source.swift
+//  shell
+//
+//  Created by Nicolas Holzschuch on 16/01/2022.
+//  Copyright © 2022 Nicolas Holzschuch. All rights reserved.
+//
+
+import Foundation
+import ios_system
+
+
+func convertCArguments(argc: Int32, argv: UnsafeMutablePointer<UnsafeMutablePointer<Int8>?>?) -> [String]? {
+    
+    var args = [String]()
+    
+    for i in 0..<Int(argc) {
+        
+        guard let argC = argv?[i] else {
+            return nil
+        }
+        
+        let arg = String(cString: argC)
+        
+        args.append(arg)
+        
+    }
+    return args
+}
+
+// TODO: create commands makeGlobal, makeLocal in libc_replacement
+
+// Small replacement for the "source" shell command.
+// Everything that affects the current shell should affect the current shell (for now: setenv and cd).
+// Files with "if" / "while" commands are going to fail.
+@_cdecl("source")
+public func source(argc: Int32, argv: UnsafeMutablePointer<UnsafeMutablePointer<Int8>?>?) -> Int32 {
+    let shortUsage = "usage: source file [file2] [file3]\n"
+    guard let args = convertCArguments(argc: argc, argv: argv) else {
+        fputs(shortUsage, thread_stdout)
+        return 0
+    }
+    if args.count == 1 {
+        fputs(shortUsage, thread_stdout)
+        return 0
+    }
+    // To make environment global, set environment[current_pid] to null, restore afterwards
+    makeGlobal()  // setenv commands go global
+    for i in 1..<args.count {
+        let fileName = URL(fileURLWithPath: args[i])
+        if (FileManager().fileExists(atPath: fileName.path)) {
+            do {
+                let contentOfFile = try String(contentsOf: fileName, encoding: String.Encoding.utf8)
+                let commands = contentOfFile.split(separator: "\n")
+                for command in commands {
+                    let trimmedCommand = command.trimmingCharacters(in: .whitespacesAndNewlines)
+                    if (trimmedCommand.count == 0) { continue } // skip white lines
+                    if (trimmedCommand.hasPrefix("#")) { continue } // skip comments
+                    // reset the LC_CTYPE (some commands (luatex) can change it):
+                    setenv("LC_CTYPE", "UTF-8", 1);
+                    setlocale(LC_CTYPE, "UTF-8");
+                    // Todo: make cd globzl: ???
+                    let pid = ios_fork()
+                    _ = ios_system(trimmedCommand)
+                    fflush(thread_stdout)
+                    ios_waitpid(pid)
+                    ios_releaseThreadId(pid)
+                }
+            }
+            catch {
+                fputs("source: error loading \(fileName).", thread_stderr)
+            }
+        } else {
+            fputs("source: file \(fileName) not found.", thread_stderr)
+        }
+    }
+    makeLocal() // back to local
+    newPreviousDirectory() // make directory changes permanent
+    return 0
+}
+
+// Now check that it *does* change the environment when run. Should not. Might have to be edited.
+// HOW? detect "setenv" and "cd"?