diff --git a/package-lock.json b/package-lock.json
index 3776dab..daf7bbb 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "frida-cshell",
-  "version": "1.4.1",
+  "version": "1.4.2",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "frida-cshell",
-      "version": "1.4.1",
+      "version": "1.4.2",
       "devDependencies": {
         "@eslint/js": "^9.10.0",
         "@types/frida-gum": "^18.7",
diff --git a/package.json b/package.json
index 53cd52d..be9d960 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "frida-cshell",
-  "version": "1.4.1",
+  "version": "1.4.2",
   "description": "Frida's CShell",
   "scripts": {
     "prepare": "npm run build && npm run version && npm run package && npm run copy",
diff --git a/src/breakpoints/bp.ts b/src/breakpoints/bp.ts
index e082d0e..33f13ac 100644
--- a/src/breakpoints/bp.ts
+++ b/src/breakpoints/bp.ts
@@ -191,13 +191,16 @@ export class Bp {
   private startCoverage(threadId: ThreadId, ctx: CpuContext) {
     Output.clearLine();
     Output.writeln(Output.yellow('-'.repeat(80)));
-    Output.write(`${Output.yellow('|')} Start Trace `);
-    Output.write(`${Output.green(`#${this._idx}`)} `);
-    Output.write(`[${this._type}] `);
-    Output.write(`${Output.yellow(this.literal)} `);
-    Output.write(`@ $pc=${Output.blue(Format.toHexString(ctx.pc))} `);
-    Output.write(`$tid=${threadId}, depth=${this._depth}`);
-    Output.writeln();
+    Output.writeln(
+      [
+        `${Output.yellow('|')} Start Trace`,
+        Output.green(`#${this._idx}`),
+        `[${this._type}]`,
+        Output.yellow(this.literal),
+        `@ $pc=${Output.blue(Format.toHexString(ctx.pc))}`,
+        `$tid=${threadId}, depth=${this._depth}`,
+      ].join(' '),
+    );
     Output.writeln(Output.yellow('-'.repeat(80)));
   }
 
@@ -212,14 +215,16 @@ export class Bp {
       Output.writeln(Output.blue('-'.repeat(80)));
       Output.clearLine();
 
-      Output.writeln(Output.yellow('-'.repeat(80)));
-      Output.write(`${Output.yellow('|')} Stop Trace `);
-      Output.write(`${Output.green(`#${this._idx}`)} `);
-      Output.write(`[${this._type}] `);
-      Output.write(`${Output.yellow(this.literal)} `);
-      Output.write(`@ $pc=${Output.blue(Format.toHexString(ctx.pc))} `);
-      Output.write(`$tid=${threadId}`);
-      Output.writeln();
+      Output.writeln(
+        [
+          `${Output.yellow('|')} Stop Trace`,
+          Output.green(`#${this._idx}`),
+          `[${this._type}]`,
+          Output.yellow(this.literal),
+          `@ $pc=${Output.blue(Format.toHexString(ctx.pc))}`,
+          `$tid=${threadId}, depth=${this._depth}`,
+        ].join(' '),
+      );
       Output.writeln(Output.yellow('-'.repeat(80)));
 
       Traces.delete(threadId);
@@ -239,13 +244,16 @@ export class Bp {
     else if (this._hits > 0) this._hits--;
     Output.clearLine();
     Output.writeln(Output.yellow('-'.repeat(80)));
-    Output.write(`${Output.yellow('|')} Break `);
-    Output.write(`${Output.green(`#${this._idx}`)} `);
-    Output.write(`[${this._type}] `);
-    Output.write(`${Output.yellow(this.literal)} `);
-    Output.write(`@ $pc=${Output.blue(Format.toHexString(ctx.pc))} `);
-    Output.write(`$tid=${threadId}`);
-    Output.writeln();
+    Output.writeln(
+      [
+        `${Output.yellow('|')} Break`,
+        Output.green(`#${this._idx}`),
+        `[${this._type}]`,
+        Output.yellow(this.literal),
+        `@ $pc=${Output.blue(Format.toHexString(ctx.pc))}`,
+        `$tid=${threadId}`,
+      ].join(' '),
+    );
     Output.writeln(Output.yellow('-'.repeat(80)));
     Regs.setThreadId(threadId);
     Regs.setContext(ctx);
@@ -275,7 +283,7 @@ export class Bp {
     } catch (error) {
       if (error instanceof Error) {
         Output.writeln(`ERROR: ${error.message}`);
-        Output.writeln(`${error.stack}`, true);
+        Output.verboseWriteln(`${error.stack}`);
       } else {
         Output.writeln(`ERROR: Unknown error`);
       }
@@ -325,13 +333,16 @@ export class Bp {
 
     Output.clearLine();
     Output.writeln(Output.yellow('-'.repeat(80)));
-    Output.write(`${Output.yellow('|')} Break `);
-    Output.write(`${Output.green(`#${this._idx}`)} `);
-    Output.write(`[${this._type}] `);
-    Output.write(`${Output.yellow(this.literal)} `);
-    Output.write(`@ $pc=${Output.blue(Format.toHexString(details.from))} `);
-    Output.write(`$addr=${Output.blue(Format.toHexString(details.address))}`);
-    Output.writeln();
+    Output.writeln(
+      [
+        `${Output.yellow('|')} Break`,
+        Output.green(`#${this._idx}`),
+        `[${this._type}]`,
+        Output.yellow(this.literal),
+        `@ $pc=${Output.blue(Format.toHexString(details.from))}`,
+        `$addr=${Output.blue(Format.toHexString(details.address))}`,
+      ].join(' '),
+    );
     Output.writeln(Output.yellow('-'.repeat(80)));
     Regs.setAddress(details.address);
     Regs.setPc(details.from);
diff --git a/src/cmdlets/assembly.ts b/src/cmdlets/assembly.ts
index 4134c28..588688c 100644
--- a/src/cmdlets/assembly.ts
+++ b/src/cmdlets/assembly.ts
@@ -10,8 +10,7 @@ const USAGE: string = `Usage: l
 
 l address <bytes> - show disassembly listing
   address   the address/symbol to disassemble
-  bytes     the number of instructions to disassemble (default ${DEFAULT_LENGTH})
-`;
+  bytes     the number of instructions to disassemble (default ${DEFAULT_LENGTH})`;
 
 export class AssemblyCmdLet extends CmdLet {
   name = 'l';
@@ -72,6 +71,7 @@ export class AssemblyCmdLet extends CmdLet {
 
         Output.writeln(
           `${Output.bold(idx)}: ${Output.green(Format.toHexString(cursor))}: ${Output.yellow(insn.toString().padEnd(40))} ${Output.blue(bytesStr)}`,
+          true,
         );
 
         cursor = cursor.add(insn.size);
@@ -125,7 +125,7 @@ export class AssemblyCmdLet extends CmdLet {
   }
 
   public usage(): Var {
-    Output.write(USAGE);
+    Output.writeln(USAGE);
     return Var.ZERO;
   }
 }
diff --git a/src/cmdlets/bp.ts b/src/cmdlets/bp.ts
index 9a5d2ac..b6b282e 100644
--- a/src/cmdlets/bp.ts
+++ b/src/cmdlets/bp.ts
@@ -76,7 +76,7 @@ abstract class TypedBpCmdLet extends CmdLet implements InputInterceptLine {
       );
       Bps.all()
         .filter(bp => bp.type === this.bpType)
-        .forEach(bp => Output.writeln(bp.toString()));
+        .forEach(bp => Output.writeln(bp.toString(), true));
       return Var.ZERO;
     } else {
       const bp = Bps.get(this.bpType, index);
@@ -90,7 +90,7 @@ abstract class TypedBpCmdLet extends CmdLet implements InputInterceptLine {
   public usage(): Var {
     const create = this.usageCreate();
     const modify = this.usageModify();
-    const INSN_BP_USAGE: string = `Usage: ${this.name}
+    const USAGE: string = `Usage: ${this.name}
 ${Output.bold('show:')}
 
 ${this.name} - show all ${this.bpType} breakpoints
@@ -109,9 +109,9 @@ ${Output.bold('delete:')}
 ${this.name} ${NUM_CHAR}n # - delete a ${this.bpType} breakpoint
    ${NUM_CHAR}n      the number of the breakpoint to delete
 
-${Output.bold('NOTE:')} Set hits to '*' for unlimited breakpoint.
-`;
-    Output.write(INSN_BP_USAGE);
+${Output.bold('NOTE:')} Set hits to '*' for unlimited breakpoint.`;
+
+    Output.writeln(USAGE);
     return Var.ZERO;
   }
 
diff --git a/src/cmdlets/bt.ts b/src/cmdlets/bt.ts
index 712c6a8..69e10e3 100644
--- a/src/cmdlets/bt.ts
+++ b/src/cmdlets/bt.ts
@@ -9,8 +9,7 @@ const USAGE: string = `Usage: bt
 bt - show the backtrace for the current thread in a breakpoint
 
 bt name - show backtrace for thread
-  thread   the name of the thread to show backtrace for
-`;
+  thread   the name of the thread to show backtrace for`;
 
 export class BtCmdLet extends CmdLet {
   name = 'bt';
@@ -51,17 +50,20 @@ export class BtCmdLet extends CmdLet {
       .forEach(s => {
         const prefix = s.moduleName === null ? '' : `${s.moduleName}!`;
         const name = `${prefix}${s.name}`;
-        Output.write(
-          `${Output.green(name.padEnd(40, '.'))} ${Output.yellow(Format.toHexString(s.address))}`,
-        );
+        let fileInfo = '';
         if (s.fileName !== null && s.lineNumber !== null) {
           if (s.fileName.length !== 0 && s.lineNumber !== 0) {
-            Output.write(
-              `\t${Output.blue(s.fileName)}:${Output.blue(s.lineNumber.toString())} `,
-            );
+            fileInfo = `\t${Output.blue(s.fileName)}:${Output.blue(s.lineNumber.toString())}`;
           }
         }
-        Output.writeln();
+        Output.writeln(
+          [
+            Output.green(name.padEnd(40, '.')),
+            Output.yellow(Format.toHexString(s.address)),
+            fileInfo,
+          ].join(' '),
+          true,
+        );
       });
   }
 
@@ -100,7 +102,7 @@ export class BtCmdLet extends CmdLet {
   }
 
   public usage(): Var {
-    Output.write(USAGE);
+    Output.writeln(USAGE);
     return Var.ZERO;
   }
 }
diff --git a/src/cmdlets/copy.ts b/src/cmdlets/copy.ts
index 1c40b92..e84abf5 100644
--- a/src/cmdlets/copy.ts
+++ b/src/cmdlets/copy.ts
@@ -10,8 +10,7 @@ const USAGE: string = `Usage: cp
 cp dest src bytes - copy data
   dest   the address/symbol to write to
   src    the address/symbol to read from
-  bytes    the numer of bytes to read
-`;
+  bytes    the numer of bytes to read`;
 
 export class CopyCmdLet extends CmdLet {
   name = 'cp';
@@ -43,7 +42,7 @@ export class CopyCmdLet extends CmdLet {
   }
 
   public usage(): Var {
-    Output.write(USAGE);
+    Output.writeln(USAGE);
     return Var.ZERO;
   }
 }
diff --git a/src/cmdlets/dump.ts b/src/cmdlets/dump.ts
index 8eacdff..c497ff0 100644
--- a/src/cmdlets/dump.ts
+++ b/src/cmdlets/dump.ts
@@ -5,6 +5,7 @@ import { Token } from '../io/token.js';
 import { Var } from '../vars/var.js';
 import { Mem } from '../memory/mem.js';
 
+const ROW_WIDTH: number = 16;
 const DEFAULT_COUNT: number = 32;
 
 const USAGE: string = `Usage: d
@@ -16,8 +17,7 @@ d address <bytes> - show data
 d address bytes <width> - show data
   adress   the address/symbol to read from
   count    the count of fields to read (default ${DEFAULT_COUNT})
-  width    the width of each field in the output (1, 2, 4 or 8)
-`;
+  width    the width of each field in the output (1, 2, 4 or 8)`;
 
 export class DumpCmdLet extends CmdLet {
   name = 'd';
@@ -45,65 +45,88 @@ export class DumpCmdLet extends CmdLet {
       const length = count * width;
       const bytes = Mem.readBytes(address, length);
 
-      switch (width) {
-        case 1: {
-          const dump = hexdump(bytes.buffer as ArrayBuffer, {
-            length,
-            header: true,
-            ansi: true,
-            address: address,
-          });
-          const prefixed = dump.replace(
-            new RegExp('\\n', 'g'),
-            `\n${Output.green('0x')}`,
-          );
-          Output.writeln(`  ${prefixed}`);
-          break;
-        }
-        default: {
-          const output = Memory.alloc(length);
-          output.writeByteArray(bytes.buffer as ArrayBuffer);
-          Output.write(' '.repeat(2 + Process.pointerSize * 2));
-          for (let i = 0; i < 16; i++) {
-            if (i % width !== 0) continue;
-            const hdr = i.toString(16).toUpperCase();
-            const padLen = width * 2 + 1 - hdr.length;
-            Output.write(` ${hdr.padStart(padLen, ' ')}`);
-          }
-          for (let i = 0; i < count; i++) {
-            const offset = i * width;
-            if (offset % 16 == 0) {
-              Output.writeln();
-              Output.write(
-                `${Output.green(Format.toHexString(address.add(offset)))} `,
-              );
-            }
+      const output = Memory.alloc(length);
+      output.writeByteArray(bytes.buffer as ArrayBuffer);
+      const headerPrefix = ' '.repeat(1 + Process.pointerSize * 2);
+      const headers = [...Array(ROW_WIDTH).keys()]
+        .map(i => {
+          if (i % width !== 0) return '';
+          const hdr = i.toString(16).toUpperCase();
+          const padLen = width * 2 + 1 - hdr.length;
+          return ` ${hdr.padStart(padLen, ' ')}`;
+        })
+        .join('');
+      const byteHeaders = width === 1 ? '0123456789ABCDEF' : '';
+      Output.writeln([headerPrefix, headers, byteHeaders].join(' '), true);
+
+      const startAddress = address.and(~(ROW_WIDTH - 1));
+      const endAddress = address
+        .add(length)
+        .add(ROW_WIDTH - 1)
+        .and(~(ROW_WIDTH - 1));
+      const numChunks = endAddress.sub(startAddress).toUInt32() / ROW_WIDTH;
 
-            const cursor = output.add(offset);
+      const rows = [...Array(numChunks).keys()]
+        .map(i => {
+          return startAddress.add(i * ROW_WIDTH);
+        })
+        .map(rowAddress => {
+          const headerPrefix = `${Output.green(Format.toHexString(rowAddress))}`;
+          const values = [...Array(ROW_WIDTH / width).keys()].map(i => {
+            const offset = i * width;
+            const rowCursor = rowAddress.add(offset);
+            const limit = address.add(length);
+            if (rowCursor < address) return ''.padStart(width * 2, ' ');
+            if (rowCursor >= limit) return ''.padStart(width * 2, ' ');
             switch (width) {
+              case 1: {
+                const val = rowCursor.readU8();
+                const str = val.toString(16).padStart(2, '0');
+                return `${Output.yellow(str)}`;
+              }
               case 2: {
-                const val = cursor.readU16();
+                const val = rowCursor.readU16();
                 const str = val.toString(16).padStart(4, '0');
-                Output.write(`${Output.yellow(str)} `);
-                break;
+                return `${Output.yellow(str)}`;
               }
               case 4: {
-                const val = cursor.readU32();
+                const val = rowCursor.readU32();
                 const str = val.toString(16).padStart(8, '0');
-                Output.write(`${Output.yellow(str)} `);
-                break;
+                return `${Output.yellow(str)}`;
               }
               case 8: {
-                const val = cursor.readU64();
+                const val = rowCursor.readU64();
                 const str = val.toString(16).padStart(16, '0');
-                Output.write(`${Output.yellow(str)} `);
-                break;
+                return `${Output.yellow(str)}`;
+              }
+              default: {
+                throw new Error(`invalid width: ${width}`);
               }
             }
+          });
+          if (width === 1) {
+            const hexDigits = [...Array(ROW_WIDTH).keys()]
+              .map(i => {
+                const rowCursor = rowAddress.add(i);
+                const limit = address.add(length);
+                if (rowCursor < address) return ' ';
+                if (rowCursor >= limit) return ' ';
+                const val = rowCursor.readU8();
+                if (val >= 32 && val <= 126) {
+                  return String.fromCharCode(val);
+                } else {
+                  return '.';
+                }
+              })
+              .join('');
+            return `${headerPrefix} ${values.join(' ')} ${Output.yellow(hexDigits)}`;
+          } else {
+            return `${headerPrefix} ${values.join(' ')}`;
           }
-          Output.writeln();
-        }
-      }
+        });
+      rows.forEach(l => {
+        Output.writeln(l, true);
+      });
     } catch (error) {
       throw new Error(
         `failed to read ${Format.toHexString(count)} bytes from ${Format.toHexString(address)}, ${error}`,
@@ -112,7 +135,7 @@ export class DumpCmdLet extends CmdLet {
   }
 
   public usage(): Var {
-    Output.write(USAGE);
+    Output.writeln(USAGE);
     return Var.ZERO;
   }
 }
diff --git a/src/cmdlets/fd.ts b/src/cmdlets/fd.ts
index 592e0fd..3a71849 100644
--- a/src/cmdlets/fd.ts
+++ b/src/cmdlets/fd.ts
@@ -19,8 +19,7 @@ const USAGE: string = `Usage: fd
 fd - show all the open file descriptors for the process
 
 fd idx - show the given file descriptor
-  idx    the number of file descriptor to show
-`;
+  idx    the number of file descriptor to show`;
 
 type Fds = {
   [key: number]: string;
@@ -51,7 +50,14 @@ export class FdCmdLet extends CmdLet {
     if (v0 === null) {
       const fds = this.readFds();
       for (const [fd, path] of Object.entries(fds)) {
-        Output.writeln(`Fd: ${fd.toString().padStart(3, ' ')}, Path: ${path}`);
+        Output.writeln(
+          [
+            'Fd: ',
+            `${Output.yellow(fd.toString().padStart(3, ' '))},`,
+            `Path: ${Output.blue(path)}`,
+          ].join(' '),
+          true,
+        );
       }
       return Var.ZERO;
     } else {
@@ -59,7 +65,13 @@ export class FdCmdLet extends CmdLet {
       const path = this.readFds()[fd];
       if (path === undefined) throw new Error(`fd: ${fd} not found`);
 
-      Output.writeln(`Fd: ${fd.toString().padStart(3, ' ')}, Path: ${path}`);
+      Output.writeln(
+        [
+          'Fd: ',
+          `${Output.yellow(fd.toString().padStart(3, ' '))},`,
+          `Path: ${Output.blue(path)}`,
+        ].join(' '),
+      );
 
       return new Var(uint64(fd), `Fd: ${fd}`);
     }
@@ -218,7 +230,7 @@ export class FdCmdLet extends CmdLet {
   }
 
   public usage(): Var {
-    Output.write(USAGE);
+    Output.writeln(USAGE);
     return Var.ZERO;
   }
 
diff --git a/src/cmdlets/grep.ts b/src/cmdlets/grep.ts
new file mode 100644
index 0000000..2e9e32d
--- /dev/null
+++ b/src/cmdlets/grep.ts
@@ -0,0 +1,47 @@
+import { CmdLet } from '../commands/cmdlet.js';
+import { Output } from '../io/output.js';
+import { Token } from '../io/token.js';
+import { Var } from '../vars/var.js';
+
+const USAGE: string = `Usage: grep
+
+grep - clear output filter
+
+grep regex - filter output
+  regex      the regex to use to filter the output`;
+
+export class GrepCmdLet extends CmdLet {
+  name = 'grep';
+  category = 'misc';
+  help = 'filter output';
+
+  public runSync(tokens: Token[]): Var {
+    const vars = this.transformOptional(tokens, [], [this.parseLiteral]);
+    if (vars === null) return this.usage();
+    const [_, [filter]] = vars as [[], [string | null]];
+    if (filter === null) {
+      Output.clearFilter();
+      Output.writeln('output filter cleared');
+    } else {
+      try {
+        Output.setFilter(filter);
+        Output.writeln(
+          [
+            'output filter set to ',
+            Output.blue("'"),
+            Output.green(filter),
+            Output.blue("'"),
+          ].join(''),
+        );
+      } catch {
+        Output.writeln(`invalid regex: ${filter}`);
+      }
+    }
+    return Var.ZERO;
+  }
+
+  public usage(): Var {
+    Output.writeln(USAGE);
+    return Var.ZERO;
+  }
+}
diff --git a/src/cmdlets/history.ts b/src/cmdlets/history.ts
index 1d6c1d3..ef67684 100644
--- a/src/cmdlets/history.ts
+++ b/src/cmdlets/history.ts
@@ -9,8 +9,7 @@ const USAGE: string = `Usage: h
 h - show history
 
 h index - rerun history item
-  index   the index of the item to rerun
-`;
+  index   the index of the item to rerun`;
 
 export class HistoryCmdLet extends CmdLet {
   name = 'h';
@@ -29,7 +28,10 @@ export class HistoryCmdLet extends CmdLet {
     if (v0 === null) {
       const history = Array.from(History.all());
       for (const [i, value] of history.entries()) {
-        Output.writeln(`${i.toString().padStart(3, ' ')}: ${value}`);
+        Output.writeln(
+          [`${i.toString().padStart(3, ' ')}:`, value].join(' '),
+          true,
+        );
       }
       return Var.ZERO;
     } else {
@@ -40,7 +42,7 @@ export class HistoryCmdLet extends CmdLet {
   }
 
   public usage(): Var {
-    Output.write(USAGE);
+    Output.writeln(USAGE);
     return Var.ZERO;
   }
 }
diff --git a/src/cmdlets/js.ts b/src/cmdlets/js.ts
index e733a53..3b9792b 100644
--- a/src/cmdlets/js.ts
+++ b/src/cmdlets/js.ts
@@ -55,12 +55,12 @@ import { ThreadCmdLet } from './thread.js';
 import { VarCmdLet } from './var.js';
 import { VmCmdLet } from './vm.js';
 import { WriteCmdLet } from './write.js';
+import { GrepCmdLet } from './grep.js';
 
 const USAGE: string = `Usage: js
 
 js path - load JS script
-  path      the absolute path of the script to load (note that paths with spaces must be quoted)
-`;
+  path      the absolute path of the script to load (note that paths with spaces must be quoted)`;
 
 export class JsCmdLet extends CmdLet {
   name = 'js';
@@ -97,6 +97,7 @@ export class JsCmdLet extends CmdLet {
       Format: Format,
       FunctionEntryBpCmdLet: FunctionEntryBpCmdLet,
       FunctionExitBpCmdLet: FunctionExitBpCmdLet,
+      GrepCmdLet: GrepCmdLet,
       HelpCmdLet: HelpCmdLet,
       History: History,
       HistoryCmdLet: HistoryCmdLet,
@@ -147,7 +148,7 @@ export class JsCmdLet extends CmdLet {
   }
 
   public usage(): Var {
-    Output.write(USAGE);
+    Output.writeln(USAGE);
     return Var.ZERO;
   }
 }
diff --git a/src/cmdlets/ld.ts b/src/cmdlets/ld.ts
index bc29a53..4a4b5f6 100644
--- a/src/cmdlets/ld.ts
+++ b/src/cmdlets/ld.ts
@@ -8,8 +8,7 @@ const USAGE: string = `Usage: ld
 ld - load a module
 
 ld path - load a module
-  path      the absolute path of the module to load (note that paths with spaces must be quoted)
-`;
+  path      the absolute path of the module to load (note that paths with spaces must be quoted)`;
 
 export class LdCmdLet extends CmdLet {
   name = 'ld';
@@ -33,7 +32,7 @@ export class LdCmdLet extends CmdLet {
   }
 
   public usage(): Var {
-    Output.write(USAGE);
+    Output.writeln(USAGE);
     return Var.ZERO;
   }
 }
diff --git a/src/cmdlets/math.ts b/src/cmdlets/math.ts
index 80c2546..0267eb9 100644
--- a/src/cmdlets/math.ts
+++ b/src/cmdlets/math.ts
@@ -34,9 +34,8 @@ abstract class BinaryOpCmdLet extends CmdLet {
 
 ${this.name} op1 op2 - ${this.OPERATION} two values together
   op1   the first operand on which to perform the operation
-  op2   the second operand on which to perform the operation
-`;
-    Output.write(usage);
+  op2   the second operand on which to perform the operation`;
+    Output.writeln(usage);
     return Var.ZERO;
   }
 
@@ -105,9 +104,8 @@ abstract class UnaryOpCmdLet extends CmdLet {
     const usage: string = `Usage: ${this.name}
 
 ${this.name} op - perform a ${this.OPERATION} operation on an operand
-  op   the operand on which to operate
-`;
-    Output.write(usage);
+  op   the operand on which to operate`;
+    Output.writeln(usage);
     return Var.ZERO;
   }
 
@@ -420,9 +418,8 @@ export class EndianCmdLet extends UnaryOpCmdLet {
 
 ${this.name} width val - ${this.OPERATION} of an operand
   width   the width of the operand (1, 2, 4 or 8)
-  op      the operand on which to perform the operation
-`;
-    Output.write(usage);
+  op      the operand on which to perform the operation`;
+    Output.writeln(usage);
     return Var.ZERO;
   }
 }
diff --git a/src/cmdlets/mod.ts b/src/cmdlets/mod.ts
index faea3f4..36938f9 100644
--- a/src/cmdlets/mod.ts
+++ b/src/cmdlets/mod.ts
@@ -13,8 +13,7 @@ mod address - show module for address
   address   the address/symbol to show module information for
 
 mod name - show named module
-  name      the name of the module to show information for
-`;
+  name      the name of the module to show information for`;
 
 export class ModCmdLet extends CmdLet {
   name = 'mod';
@@ -54,15 +53,17 @@ export class ModCmdLet extends CmdLet {
     return v0;
   }
 
-  private printModule(m: Module) {
+  private printModule(m: Module, filtered: boolean = true) {
     const limit = m.base.add(m.size);
-    Output.write(
-      `${Output.green(Format.toHexString(m.base))}-${Output.green(Format.toHexString(limit))} `,
+    Output.writeln(
+      [
+        `${Output.green(Format.toHexString(m.base))}-${Output.green(Format.toHexString(limit))}`,
+        Output.bold(Format.toSize(m.size)),
+        Output.yellow(m.name.padEnd(30, ' ')),
+        Output.blue(m.path),
+      ].join(' '),
+      filtered,
     );
-    Output.write(`${Output.bold(Format.toSize(m.size))} `);
-    Output.write(`${Output.yellow(m.name.padEnd(30, ' '))} `);
-    Output.write(`${Output.blue(m.path)}`);
-    Output.writeln();
   }
 
   private runShowNamed(tokens: Token[]): Var | null {
@@ -86,7 +87,7 @@ export class ModCmdLet extends CmdLet {
       );
       modules.sort();
       modules.forEach(m => {
-        this.printModule(m);
+        this.printModule(m, true);
       });
       if (modules.length === 1) {
         const module = modules[0] as Module;
@@ -110,7 +111,7 @@ export class ModCmdLet extends CmdLet {
   }
 
   public usage(): Var {
-    Output.write(USAGE);
+    Output.writeln(USAGE);
     return Var.ZERO;
   }
 }
diff --git a/src/cmdlets/print.ts b/src/cmdlets/print.ts
index f5d8c98..42be11e 100644
--- a/src/cmdlets/print.ts
+++ b/src/cmdlets/print.ts
@@ -7,8 +7,7 @@ const USAGE: string = `Usage: p
 p - print an expression
 
 p exp - print an expression
-  exp   the expression to print
-`;
+  exp   the expression to print`;
 
 export class PrintCmdLet extends CmdLet {
   name = 'p';
@@ -30,7 +29,7 @@ export class PrintCmdLet extends CmdLet {
   }
 
   public usage(): Var {
-    Output.write(USAGE);
+    Output.writeln(USAGE);
     return Var.ZERO;
   }
 }
diff --git a/src/cmdlets/read.ts b/src/cmdlets/read.ts
index 6e5a6bd..5ea923f 100644
--- a/src/cmdlets/read.ts
+++ b/src/cmdlets/read.ts
@@ -66,7 +66,7 @@ r n address - read 'n' bytes from memory
   n         the number of bytes to read (1, 2, 4 or 8).
   address   the address/symbol to read from`;
 
-    Output.write(usage);
+    Output.writeln(usage);
     return Var.ZERO;
   }
 }
diff --git a/src/cmdlets/reg.ts b/src/cmdlets/reg.ts
index d1420e4..03f7027 100644
--- a/src/cmdlets/reg.ts
+++ b/src/cmdlets/reg.ts
@@ -13,8 +13,7 @@ R name - display the value of a named register
 
 R name value - assign a value to a register
   name    the name of the register to assign
-  value   the value to assign
-`;
+  value   the value to assign`;
 
 export class RegCmdLet extends CmdLet {
   name = 'R';
@@ -36,6 +35,7 @@ export class RegCmdLet extends CmdLet {
         for (const [key, value] of Regs.all()) {
           Output.writeln(
             `${Output.bold(key.padEnd(4, ' '))}: ${value.toString()}`,
+            true,
           );
         }
         return Vars.getRet();
@@ -63,7 +63,7 @@ export class RegCmdLet extends CmdLet {
   }
 
   public usage(): Var {
-    Output.write(USAGE);
+    Output.writeln(USAGE);
     return Var.ZERO;
   }
 }
diff --git a/src/cmdlets/sh.ts b/src/cmdlets/sh.ts
index 9383113..d3f6b1b 100644
--- a/src/cmdlets/sh.ts
+++ b/src/cmdlets/sh.ts
@@ -17,8 +17,7 @@ const WNOHANG: number = 1;
 type Pipe = { readFd: number; writeFd: number };
 
 const USAGE: string = `Usage: fd
-sh - run a shell
-`;
+sh - run a shell`;
 
 export class ShCmdLet extends CmdLet {
   name = 'sh';
@@ -88,7 +87,7 @@ export class ShCmdLet extends CmdLet {
       throw new Error(`failed to getenv("SHELL"), errno: ${getenvErrno}`);
 
     const shellPath = shellVar.readUtf8String();
-    Output.writeln(`SHELL: ${shellPath}`, true);
+    Output.verboseWriteln(`SHELL: ${shellPath}`);
 
     if (shellPath === null) throw new Error('failed to read SHELL');
 
@@ -206,7 +205,7 @@ export class ShCmdLet extends CmdLet {
       if (this.fnClose === null || this.fnWaitPid === null)
         throw new Error('failed to find necessary native functions');
 
-      Output.writeln(`child pid: ${childPid}`, true);
+      Output.verboseWriteln(`child pid: ${childPid}`);
       const { value: closeChildRet, errno: closeChildErrno } = this.fnClose(
         toChildReadFd,
       ) as UnixSystemFunctionResult<number>;
@@ -234,7 +233,7 @@ export class ShCmdLet extends CmdLet {
 
       Input.setInterceptRaw(onRaw);
 
-      Output.writeln(`reading pid: ${childPid}`, true);
+      Output.verboseWriteln(`reading pid: ${childPid}`);
 
       for (
         let buf = await input.read(READ_SIZE);
@@ -245,7 +244,7 @@ export class ShCmdLet extends CmdLet {
         Output.write(str);
       }
 
-      Output.writeln(`waiting pid: ${childPid}`, true);
+      Output.verboseWriteln(`waiting pid: ${childPid}`);
 
       const pStatus = Memory.alloc(INT_SIZE);
 
@@ -289,7 +288,7 @@ export class ShCmdLet extends CmdLet {
   }
 
   public usage(): Var {
-    Output.write(USAGE);
+    Output.writeln(USAGE);
     return Var.ZERO;
   }
 
diff --git a/src/cmdlets/src.ts b/src/cmdlets/src.ts
index 1b98ede..4918f7f 100644
--- a/src/cmdlets/src.ts
+++ b/src/cmdlets/src.ts
@@ -10,8 +10,7 @@ import { Vars } from '../vars/vars.js';
 const USAGE: string = `Usage: src
 
 src path - load script
-  path      the absolute path of the script to load (note that paths with spaces must be quoted)
-`;
+  path      the absolute path of the script to load (note that paths with spaces must be quoted)`;
 
 export class SrcCmdLet extends CmdLet {
   name = 'src';
@@ -58,8 +57,7 @@ export class SrcCmdLet extends CmdLet {
         if (line.length === 0) continue;
         if (line.charAt(0) === '#') continue;
 
-        Output.write(Output.bold(Input.PROMPT));
-        Output.writeln(line);
+        Output.writeln(`${Output.bold(Input.PROMPT)}${line}`);
 
         if (line.trim().length === 0) continue;
 
@@ -76,7 +74,7 @@ export class SrcCmdLet extends CmdLet {
   }
 
   public usage(): Var {
-    Output.write(USAGE);
+    Output.writeln(USAGE);
     return Var.ZERO;
   }
 }
diff --git a/src/cmdlets/string.ts b/src/cmdlets/string.ts
index a620725..f951550 100644
--- a/src/cmdlets/string.ts
+++ b/src/cmdlets/string.ts
@@ -9,8 +9,7 @@ const MAX_STRING_LENGTH: number = 1024;
 const USAGE: string = `Usage: ds
 
 ds address <bytes> - show string
-  adress   the address/symbol to show
-`;
+  adress   the address/symbol to show`;
 
 export class DumpStringCmdLet extends CmdLet {
   name = 'ds';
@@ -58,22 +57,20 @@ export class DumpStringCmdLet extends CmdLet {
         `No string found at ${Output.green(name)}: ${Output.yellow(Format.toHexString(address))}`,
       );
     } else {
-      Output.write(Output.green(name));
-      Output.write(' = ');
-      Output.write(Output.blue("'"));
-      Output.write(Output.yellow(value));
-      Output.write(Output.blue("'"));
-      Output.write(', length: ');
-      Output.write(Output.blue(value.length.toString()));
-      Output.write(' (');
-      Output.write(Output.blue(`0x${value.length.toString(16)}`));
-      Output.write(')');
-      Output.writeln();
+      Output.writeln(
+        [
+          Output.green(name),
+          '=',
+          `${Output.blue("'")}${Output.yellow(value)}${Output.blue("'")},`,
+          `length: ${Output.blue(value.length.toString())},`,
+          `(${Output.blue(`0x${value.length.toString(16)}`)})`,
+        ].join(' '),
+      );
     }
   }
 
   public usage(): Var {
-    Output.write(USAGE);
+    Output.writeln(USAGE);
     return Var.ZERO;
   }
 }
diff --git a/src/cmdlets/sym.ts b/src/cmdlets/sym.ts
index 4a94410..6824f13 100644
--- a/src/cmdlets/sym.ts
+++ b/src/cmdlets/sym.ts
@@ -15,8 +15,7 @@ sym name - display address information for a named symbol
   name   the name of the symbol to lookup
 
 sym addr - display symbol information associated with an address
-  addr   the address of the symbol to lookup
-`;
+  addr   the address of the symbol to lookup`;
 
 export class SymCmdLet extends CmdLet {
   name = 'sym';
@@ -148,7 +147,7 @@ export class SymCmdLet extends CmdLet {
           Output.yellow(Format.toHexString(value.address)),
           `[${Output.blue(value.type)}]`,
         ].join(' '),
-      ).forEach(s => Output.writeln(s));
+      ).forEach(s => Output.writeln(s, true));
 
       const values = Array.from(dict.values());
       if (values.length === 1) {
@@ -185,7 +184,7 @@ export class SymCmdLet extends CmdLet {
   }
 
   public usage(): Var {
-    Output.write(USAGE);
+    Output.writeln(USAGE);
     return Var.ZERO;
   }
 }
diff --git a/src/cmdlets/thread.ts b/src/cmdlets/thread.ts
index 96f808d..5d6c45a 100644
--- a/src/cmdlets/thread.ts
+++ b/src/cmdlets/thread.ts
@@ -9,8 +9,7 @@ const USAGE: string = `Usage: t
 t - show all threads
 
 t name - show named thread
-  name  the name of the thread to show information for
-`;
+  name  the name of the thread to show information for`;
 
 export class ThreadCmdLet extends CmdLet {
   name = 't';
@@ -49,7 +48,7 @@ export class ThreadCmdLet extends CmdLet {
     }
   }
 
-  private printThread(t: ThreadDetails) {
+  private printThread(t: ThreadDetails, filtered: boolean = true) {
     Output.writeln(
       [
         `${Output.yellow(t.id.toString().padStart(5, ' '))}:`,
@@ -58,6 +57,7 @@ export class ThreadCmdLet extends CmdLet {
         `pc: ${Output.yellow(Format.toHexString(t.context.pc))}`,
         `sp: ${Output.yellow(Format.toHexString(t.context.sp))}`,
       ].join(' '),
+      filtered,
     );
   }
 
@@ -78,7 +78,7 @@ export class ThreadCmdLet extends CmdLet {
       }
       default:
         matches.forEach(t => {
-          this.printThread(t);
+          this.printThread(t, true);
         });
         return Var.ZERO;
     }
@@ -99,14 +99,14 @@ export class ThreadCmdLet extends CmdLet {
       }
       default:
         threads.forEach(t => {
-          this.printThread(t);
+          this.printThread(t, true);
         });
         return Var.ZERO;
     }
   }
 
   public usage(): Var {
-    Output.write(USAGE);
+    Output.writeln(USAGE);
     return Var.ZERO;
   }
 }
diff --git a/src/cmdlets/var.ts b/src/cmdlets/var.ts
index f477a90..e3c6e72 100644
--- a/src/cmdlets/var.ts
+++ b/src/cmdlets/var.ts
@@ -17,8 +17,7 @@ v name value - assign a value to a variable
   value   the value to assign
 
 v name ${DELETE_CHAR} - delete a variable
-  name    the name of the variable to delete
-`;
+  name    the name of the variable to delete`;
 
 export class VarCmdLet extends CmdLet {
   name = 'v';
@@ -73,6 +72,7 @@ export class VarCmdLet extends CmdLet {
             `${Output.green(key.padEnd(25, ' '))}:`,
             `${Output.yellow(value.toString())}`,
           ].join(' '),
+          true,
         );
       }
       return Vars.getRet();
@@ -94,7 +94,7 @@ export class VarCmdLet extends CmdLet {
   }
 
   public usage(): Var {
-    Output.write(USAGE);
+    Output.writeln(USAGE);
     return Var.ZERO;
   }
 }
diff --git a/src/cmdlets/verbose.ts b/src/cmdlets/verbose.ts
new file mode 100644
index 0000000..1ad6110
--- /dev/null
+++ b/src/cmdlets/verbose.ts
@@ -0,0 +1,30 @@
+import { CmdLet } from '../commands/cmdlet.js';
+import { Output } from '../io/output.js';
+import { Token } from '../io/token.js';
+import { Var } from '../vars/var.js';
+
+const USAGE: string = `Usage: verbose
+verbose - toggle verbose mode`;
+
+export class VerboseCmdLet extends CmdLet {
+  name = 'verbose';
+  category = 'misc';
+  help = 'toggle verbose mode';
+
+  public runSync(_tokens: Token[]): Var {
+    const verbose = !Output.getVerbose();
+    if (verbose) {
+      Output.writeln(`verbose mode ${Output.green('enabled')}`);
+    } else {
+      Output.writeln(`verbose mode ${Output.red('disabled')}`);
+    }
+    Output.setVerbose(verbose);
+
+    return Var.ZERO;
+  }
+
+  public usage(): Var {
+    Output.writeln(USAGE);
+    return Var.ZERO;
+  }
+}
diff --git a/src/cmdlets/vm.ts b/src/cmdlets/vm.ts
index f0d98c6..9e9bc8c 100644
--- a/src/cmdlets/vm.ts
+++ b/src/cmdlets/vm.ts
@@ -13,8 +13,7 @@ vm address - show mapping for address
   address   the address/symbol to show mapping information for
 
 vm module - show mappings for a module
-  module    the name of the module to show mapping information for
-`;
+  module    the name of the module to show mapping information for`;
 
 export class VmCmdLet extends CmdLet {
   name = 'vm';
@@ -76,20 +75,24 @@ export class VmCmdLet extends CmdLet {
     return v0;
   }
 
-  private printMapping(r: RangeDetails) {
+  private printMapping(r: RangeDetails, filter: boolean = true) {
     const limit = r.base.add(r.size);
-    Output.write(
-      `\t${Output.green(Format.toHexString(r.base))}-${Output.green(Format.toHexString(limit))} `,
-    );
-    Output.write(`${Output.bold(Output.yellow(r.protection))} `);
-    Output.write(`${Output.bold(Format.toSize(r.size))} `);
+    let fileInfo = '';
     if (r.file !== undefined) {
-      Output.write(
-        `offset: ${Output.bold(Format.toHexString(r.file.offset))}, `,
-      );
-      Output.write(`name: ${Output.blue(r.file.path)}`);
+      fileInfo = [
+        `offset: ${Output.yellow(Format.toHexString(r.file.offset))},`,
+        `name: ${Output.blue(r.file.path)}`,
+      ].join(' ');
     }
-    Output.writeln();
+    Output.writeln(
+      [
+        `\t${Output.green(Format.toHexString(r.base))}-${Output.green(Format.toHexString(limit))}`,
+        `${Output.bold(Output.yellow(r.protection))}`,
+        `${Output.bold(Format.toSize(r.size))}`,
+        fileInfo,
+      ].join(' '),
+      filter,
+    );
   }
 
   private runShowNamed(tokens: Token[]): Var | null {
@@ -99,7 +102,7 @@ export class VmCmdLet extends CmdLet {
 
     if (name === null) {
       Process.enumerateRanges('---').forEach(r => {
-        this.printMapping(r);
+        this.printMapping(r, true);
       });
       return Var.ZERO;
     } else if (Regex.isGlob(name)) {
@@ -112,7 +115,7 @@ export class VmCmdLet extends CmdLet {
       modules.sort();
       modules.forEach(m => {
         m.enumerateRanges('---').forEach(r => {
-          this.printMapping(r);
+          this.printMapping(r, true);
         });
       });
       if (modules.length === 1) {
@@ -132,14 +135,14 @@ export class VmCmdLet extends CmdLet {
       }
 
       mod.enumerateRanges('---').forEach(r => {
-        this.printMapping(r);
+        this.printMapping(r, true);
       });
       return new Var(uint64(mod.base.toString()), `Module: ${mod.name}`);
     }
   }
 
   public usage(): Var {
-    Output.write(USAGE);
+    Output.writeln(USAGE);
     return Var.ZERO;
   }
 }
diff --git a/src/cmdlets/write.ts b/src/cmdlets/write.ts
index f0fb54e..c9094ff 100644
--- a/src/cmdlets/write.ts
+++ b/src/cmdlets/write.ts
@@ -107,9 +107,8 @@ export class WriteCmdLet extends CmdLet {
 w n address value - write 'n' bytes to memory
     n        the number of bytes to read (1, 2, 4 or 8).
     address  the address/symbol to write to
-    value    the value to write
-        `;
-    Output.write(usage);
+    value    the value to write`;
+    Output.writeln(usage);
     return Var.ZERO;
   }
 }
diff --git a/src/commands/cmdlets.ts b/src/commands/cmdlets.ts
index 86850b6..0211ea4 100644
--- a/src/commands/cmdlets.ts
+++ b/src/commands/cmdlets.ts
@@ -45,6 +45,8 @@ import { JsCmdLet } from '../cmdlets/js.js';
 import { PrintCmdLet } from '../cmdlets/print.js';
 import { ShCmdLet } from '../cmdlets/sh.js';
 import { SrcCmdLet } from '../cmdlets/src.js';
+import { VerboseCmdLet } from '../cmdlets/verbose.js';
+import { GrepCmdLet } from '../cmdlets/grep.js';
 
 export class CmdLets {
   private static byName: Map<string, CmdLet> = new Map<string, CmdLet>();
@@ -65,6 +67,7 @@ export class CmdLets {
     this.registerCmdletType(EndianCmdLet);
     this.registerCmdletType(ExitCmdLet);
     this.registerCmdletType(FdCmdLet);
+    this.registerCmdletType(GrepCmdLet);
     this.registerCmdletType(FunctionEntryBpCmdLet);
     this.registerCmdletType(FunctionExitBpCmdLet);
     this.registerCmdletType(HelpCmdLet);
@@ -88,6 +91,7 @@ export class CmdLets {
     this.registerCmdletType(ThreadCmdLet);
     this.registerCmdletType(UniqueBlockTraceBpCmdLet);
     this.registerCmdletType(VarCmdLet);
+    this.registerCmdletType(VerboseCmdLet);
     this.registerCmdletType(VmCmdLet);
     this.registerCmdletType(WriteCmdLet);
     this.registerCmdletType(WriteBpCmdLet);
diff --git a/src/commands/command.ts b/src/commands/command.ts
index 5a8d8e8..b04c5a8 100644
--- a/src/commands/command.ts
+++ b/src/commands/command.ts
@@ -57,9 +57,12 @@ export class Command {
     }
 
     args.forEach((param, index) => {
-      Output.writeln(
-        `\t${index}: ${Format.toHexString(param)} ${Format.toDecString(param)}`,
-        true,
+      Output.verboseWriteln(
+        [
+          `\t${index}:`,
+          Format.toHexString(param),
+          Format.toDecString(param),
+        ].join(' '),
       );
     });
 
diff --git a/src/entrypoint.ts b/src/entrypoint.ts
index d037434..019abe6 100644
--- a/src/entrypoint.ts
+++ b/src/entrypoint.ts
@@ -25,7 +25,7 @@ rpc.exports = {
   init(stage: string, params: InitParams | null = null) {
     const verbose = params?.verbose ?? false;
     Output.setVerbose(verbose);
-    Output.writeln(`init - stage: ${stage}, verbose: ${verbose}`, true);
+    Output.verboseWriteln(`init - stage: ${stage}, verbose: ${verbose}`);
     Output.banner();
     Process.setExceptionHandler(exceptionHandler);
     SrcCmdLet.loadInitScript(DEFAULT_SRC_PATH);
diff --git a/src/io/input.ts b/src/io/input.ts
index fe738bd..726d757 100644
--- a/src/io/input.ts
+++ b/src/io/input.ts
@@ -15,6 +15,7 @@ const CLEAR_CHAR: string = 'c';
 
 export class Input {
   public static readonly PROMPT: string = '-> ';
+  public static readonly FILTERED_PROMPT: string = '~> ';
   private static readonly EDIT_PROMPT: string = '. ';
 
   private static buffer: string = '';
@@ -108,7 +109,7 @@ export class Input {
     } catch (error) {
       if (error instanceof Error) {
         Output.writeln(`ERROR: ${error.message}`);
-        Output.writeln(`${error.stack}`, true);
+        Output.verboseWriteln(`${error.stack}`);
       } else {
         Output.writeln(`ERROR: Unknown error`);
       }
@@ -120,7 +121,11 @@ export class Input {
   public static prompt() {
     Output.clearLine();
     if (this.interceptLine === null) {
-      Output.write(Output.bold(this.PROMPT));
+      if (Output.isFiltered()) {
+        Output.write(Output.bold(this.FILTERED_PROMPT));
+      } else {
+        Output.write(Output.bold(this.PROMPT));
+      }
     } else {
       Output.write(Output.bold(this.EDIT_PROMPT));
     }
diff --git a/src/io/output.ts b/src/io/output.ts
index e0e688e..ec4f3fe 100644
--- a/src/io/output.ts
+++ b/src/io/output.ts
@@ -25,6 +25,7 @@ export class Output {
 
   private static verbose: boolean = false;
   private static indent: boolean = false;
+  private static filter: RegExp | null = null;
 
   public static banner() {
     this.shell
@@ -53,30 +54,50 @@ export class Output {
     this.writeln(`\tName: ${this.green(first.name)}`);
   }
 
-  public static writeln(
-    buffer: string | null = null,
-    verbose: boolean = false,
-  ) {
-    this.write(`${buffer ?? ''}\n`, verbose);
+  public static verboseWriteln(buffer: string | null) {
+    this.dowrite(`${buffer ?? ''}\n`, true, false);
   }
 
-  public static write(buffer: string | null = null, verbose: boolean = false) {
+  public static writeln(buffer: string | null = null, filter: boolean = false) {
+    this.dowrite(`${buffer ?? ''}\n`, false, filter);
+  }
+
+  public static write(buffer: string | null = null, filter: boolean = false) {
+    this.dowrite(buffer, false, filter);
+  }
+
+  private static dowrite(
+    buffer: string | null = null,
+    verbose: boolean,
+    filter: boolean,
+  ) {
     if (verbose && !this.verbose) return;
 
     if (buffer === null) return;
 
+    const filterExpression = (l: string) =>
+      filter === false ||
+      l.length === 0 ||
+      Output.filter === null ||
+      Output.filter.test(l);
+
     if (this.indent) {
-      const trimmed = buffer.endsWith('\n')
-        ? buffer.slice(0, buffer.length - 1)
-        : buffer;
-      const fixed = trimmed.replace(
-        new RegExp('\\n', 'g'),
-        `\r\n${Output.yellow('| ')}`,
-      );
-      const output = buffer.endsWith('\n') ? `${fixed}\r\n` : fixed;
-      send(['frida:stderr', `${Output.yellow('| ')}${output}`]);
+      if (buffer.endsWith('\n')) {
+        const lines = buffer.slice(0, buffer.length - 1).split('\n');
+        const fixed = lines
+          .filter(filterExpression)
+          .join(`\r\n${Output.yellow('| ')}`);
+        send(['frida:stderr', `${Output.yellow('| ')}${fixed}\r\n`]);
+      } else {
+        const lines = buffer.split('\n');
+        const fixed = lines
+          .filter(filterExpression)
+          .join(`\r\n${Output.yellow('| ')}`);
+        send(['frida:stderr', `${Output.yellow('| ')}${fixed}`]);
+      }
     } else {
-      const fixed = buffer.replace(new RegExp('\\n', 'g'), '\r\n');
+      const lines = buffer.split('\n');
+      const fixed = lines.filter(filterExpression).join(`\r\n`);
       send(['frida:stderr', fixed]);
     }
   }
@@ -91,6 +112,10 @@ export class Output {
     Output.writeln(`ret: ${Output.bold(Vars.getRet().toString())}`);
   }
 
+  public static getVerbose(): boolean {
+    return this.verbose;
+  }
+
   public static setVerbose(verbose: boolean) {
     this.verbose = verbose;
   }
@@ -118,4 +143,16 @@ export class Output {
   public static red(input: string): string {
     return `${CharCode.RED}${input}${CharCode.RESET}`;
   }
+
+  public static setFilter(filter: string) {
+    this.filter = new RegExp(filter);
+  }
+
+  public static clearFilter() {
+    this.filter = null;
+  }
+
+  public static isFiltered() {
+    return this.filter !== null;
+  }
 }
diff --git a/src/traces/block.ts b/src/traces/block.ts
index c839f70..e59f6a7 100644
--- a/src/traces/block.ts
+++ b/src/traces/block.ts
@@ -69,11 +69,8 @@ export class BlockTrace implements Trace {
           }
           numOutput += 1;
           const idx = `${numOutput.toString().padStart(4, ' ')}. `;
-          Output.write(Output.bold(idx));
-          if (currentDepth > 0) {
-            Output.write('\t'.repeat(currentDepth));
-          }
-          Output.writeln(name);
+          const depth = currentDepth > 0 ? '\t'.repeat(currentDepth) : '';
+          Output.writeln(`${depth}${Output.bold(idx)}${name}`);
           break;
         }
         case 4: {
diff --git a/src/traces/call.ts b/src/traces/call.ts
index 624819a..a99055b 100644
--- a/src/traces/call.ts
+++ b/src/traces/call.ts
@@ -54,9 +54,10 @@ export class CallTrace implements Trace {
         if (toName === null) continue;
 
         if (first) {
+          const idx = `${numOutput.toString().padStart(4, ' ')}. `;
           const fromName = Traces.getAddressString(from as NativePointer);
           if (fromName === null) continue;
-          Output.writeln(fromName);
+          Output.writeln(`${Output.bold(idx)}${fromName}`);
           currentDepth = 1;
           first = false;
         }
@@ -66,11 +67,8 @@ export class CallTrace implements Trace {
         }
         numOutput += 1;
         const idx = `${numOutput.toString().padStart(4, ' ')}. `;
-        Output.write(Output.bold(idx));
-        if (currentDepth > 0) {
-          Output.write('\t'.repeat(currentDepth));
-        }
-        Output.writeln(toName);
+        const depth = currentDepth > 0 ? '\t'.repeat(currentDepth) : '';
+        Output.writeln(`${depth}${Output.bold(idx)}${toName}`);
       } else if (kind === 'ret') {
         if (currentDepth > 0) {
           currentDepth -= 1;