diff --git a/markdown/bitburner.ns.ls.md b/markdown/bitburner.ns.ls.md
index 16b2c4cc9..673138917 100644
--- a/markdown/bitburner.ns.ls.md
+++ b/markdown/bitburner.ns.ls.md
@@ -9,7 +9,7 @@ List files on a server.
 **Signature:**
 
 ```typescript
-ls(host: string, grep?: string): string[];
+ls(host: string, substring?: string): string[];
 ```
 
 ## Parameters
@@ -17,7 +17,7 @@ ls(host: string, grep?: string): string[];
 |  Parameter | Type | Description |
 |  --- | --- | --- |
 |  host | string | Hostname of the target server. |
-|  grep | string | _(Optional)_ A substring to search for in the filename. |
+|  substring | string | _(Optional)_ A substring to search for in the filename. |
 
 **Returns:**
 
diff --git a/markdown/bitburner.ns.md b/markdown/bitburner.ns.md
index 2da1b8ad3..c8e8c4362 100644
--- a/markdown/bitburner.ns.md
+++ b/markdown/bitburner.ns.md
@@ -135,7 +135,7 @@ export async function main(ns) {
 |  [kill(pid)](./bitburner.ns.kill.md) | Terminate the script with the provided PID. |
 |  [kill(filename, hostname, args)](./bitburner.ns.kill_1.md) | Terminate the script with the provided filename, hostname, and script arguments. |
 |  [killall(host, safetyguard)](./bitburner.ns.killall.md) | Terminate all scripts on a server. |
-|  [ls(host, grep)](./bitburner.ns.ls.md) | List files on a server. |
+|  [ls(host, substring)](./bitburner.ns.ls.md) | List files on a server. |
 |  [moveTail(x, y, pid)](./bitburner.ns.movetail.md) | Move a tail window. |
 |  [mv(host, source, destination)](./bitburner.ns.mv.md) | Move a file on the target server. |
 |  [nFormat(n, format)](./bitburner.ns.nformat.md) | Format a number using the numeral library. This function is deprecated and will be removed in 2.3. |
diff --git a/src/NetscriptFunctions.ts b/src/NetscriptFunctions.ts
index 0794f74ee..ab92731cd 100644
--- a/src/NetscriptFunctions.ts
+++ b/src/NetscriptFunctions.ts
@@ -909,74 +909,22 @@ export const ns: InternalAPI<NSFull> = {
 
       return noFailures;
     },
-  ls:
-    (ctx) =>
-    (_hostname, _grep = ""): string[] => {
-      const hostname = helpers.string(ctx, "hostname", _hostname);
-      const grep = helpers.string(ctx, "grep", _grep);
+  ls: (ctx) => (_hostname, _substring) => {
+    const hostname = helpers.string(ctx, "hostname", _hostname);
+    const substring = helpers.string(ctx, "substring", _substring ?? "");
+    const server = helpers.getServer(ctx, hostname);
 
-      const server = helpers.getServer(ctx, hostname);
+    const allFilenames = [
+      ...server.contracts.map((contract) => contract.fn),
+      ...server.messages,
+      ...server.programs,
+      ...server.scripts.map((script) => script.filename),
+      ...server.textFiles.map((textFile) => textFile.filename),
+    ];
 
-      // Get the grep filter, if one exists
-      let filter = "";
-      if (_grep !== undefined) {
-        filter = grep.toString();
-      }
-
-      const allFiles = [];
-      for (let i = 0; i < server.programs.length; i++) {
-        if (filter) {
-          if (server.programs[i].includes(filter)) {
-            allFiles.push(server.programs[i]);
-          }
-        } else {
-          allFiles.push(server.programs[i]);
-        }
-      }
-      for (let i = 0; i < server.scripts.length; i++) {
-        if (filter) {
-          if (server.scripts[i].filename.includes(filter)) {
-            allFiles.push(server.scripts[i].filename);
-          }
-        } else {
-          allFiles.push(server.scripts[i].filename);
-        }
-      }
-      for (let i = 0; i < server.messages.length; i++) {
-        if (filter) {
-          const msg = server.messages[i];
-          if (msg.includes(filter)) {
-            allFiles.push(msg);
-          }
-        } else {
-          allFiles.push(server.messages[i]);
-        }
-      }
-
-      for (let i = 0; i < server.textFiles.length; i++) {
-        if (filter) {
-          if (server.textFiles[i].fn.includes(filter)) {
-            allFiles.push(server.textFiles[i].fn);
-          }
-        } else {
-          allFiles.push(server.textFiles[i].fn);
-        }
-      }
-
-      for (let i = 0; i < server.contracts.length; ++i) {
-        if (filter) {
-          if (server.contracts[i].fn.includes(filter)) {
-            allFiles.push(server.contracts[i].fn);
-          }
-        } else {
-          allFiles.push(server.contracts[i].fn);
-        }
-      }
-
-      // Sort the files alphabetically then print each
-      allFiles.sort();
-      return allFiles;
-    },
+    if (!substring) return allFilenames.sort();
+    return allFilenames.filter((filename) => filename.includes(substring)).sort();
+  },
   getRecentScripts: () => (): RecentScript[] => {
     return recentScripts.map((rs) => ({
       timeOfDeath: rs.timeOfDeath,
diff --git a/src/ScriptEditor/NetscriptDefinitions.d.ts b/src/ScriptEditor/NetscriptDefinitions.d.ts
index b1378e821..887d0d2f9 100644
--- a/src/ScriptEditor/NetscriptDefinitions.d.ts
+++ b/src/ScriptEditor/NetscriptDefinitions.d.ts
@@ -5592,10 +5592,10 @@ export interface NS {
    * (as strings). The returned array is sorted in alphabetic order.
    *
    * @param host - Hostname of the target server.
-   * @param grep - A substring to search for in the filename.
+   * @param substring - A substring to search for in the filename.
    * @returns Array with the filenames of all files on the specified server.
    */
-  ls(host: string, grep?: string): string[];
+  ls(host: string, substring?: string): string[];
 
   /**
    * List running scripts on a server.