---
product: Chilkat
product_version: 11.7.0
language: js
language_label: JavaScript
class: UnixCompress
license: bundle
deprecated: false
reference_html: https://www.chilkatsoft.com/refdoc/jsUnixCompressRef.html
---
# Chilkat UnixCompress — JavaScript — v11.7.0

> Chilkat 11.7.0 · language=js · class=UnixCompress
> Other versions: replace `11.7.0` in this URL. Other languages: `https://www.chilkatsoft.com/ai-docs/v/11.7.0/<lang>/classes/UnixCompress.md`.
> Language-wide rules (install, unlock, error model, strings/bytes): `https://www.chilkatsoft.com/ai-docs/v/11.7.0/js/guide.md`.

## Purpose

**Compress, uncompress, and unpack legacy UNIX `.Z` files.**

`Chilkat.UnixCompress` provides UNIX `compress` and `uncompress` functionality for legacy `.Z` files. It supports file-based, memory-based, and string-based workflows, uses LZW compression, can unpack `.tar.Z` archives, and includes abort and progress-related support for longer-running operations.

**Compress to .Z**

Compress files, memory data, or strings into UNIX `.Z` format using LZW compression.

**Uncompress .Z data**

Expand UNIX-compressed data back to files, memory, byte arrays, or text depending on the application workflow.

**File workflows**

Compress and uncompress directly between input and output files when working with existing filesystem data.

**Memory workflows**

Work with compressed or uncompressed byte data in memory when temporary files are not desired.

**String workflows**

Compress and uncompress text using an explicit character set so string data round-trips correctly.

**Unpack tar.Z archives**

Use `UnTarZ` to decompress and extract legacy `.tar.Z` archives in a single workflow.

**Common pattern:** Use `UnixCompress` when the data is in classic UNIX `.Z` format or when a `.tar.Z` archive must be unpacked. Use `Chilkat.Gzip` for `.gz` and `.tar.gz` files, `Chilkat.Bz2` for `.bz2` files, and `Chilkat.Compression` for raw compression algorithms and general-purpose compression workflows.

For an extended overview, see [UnixCompress Class Overview](https://www.chilkatsoft.com/unixcompress_class_overview.asp).

## Object creation, unlocking and error handling

**Object Creation**

Note: This is intended for running within a [Chilkat.Js embedded JavaScript engine](https://www.chilkatsoft.com/chilkat_javascript_engine.asp).

```
var obj = new CkUnixCompress();
```

Call `Global.UnlockBundle` once at the start of the program, before using this or any other Chilkat class. Any string unlocks a fully functional 30-day trial; a purchased unlock code is used in production. See `guide.md` for the exact code in JavaScript.

How failure is reported depends on the method's return type and is stated in the note under each method below. In every case the diagnostic text is in the `LastErrorText` property of the object whose method was called.

## Members common to every Chilkat class

Documented once per language in `common-members.md`; listed here so this page is self-contained.

| Property | Signature | Access | Meaning |
|---|---|---|---|
| `DebugLogFilePath` | `DebugLogFilePath` | read/write | If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. |
| `LastErrorHtml` | `LastErrorHtml` | read-only | Provides HTML-formatted information about the last called method or property. |
| `LastErrorText` | `LastErrorText` | read-only | Provides plain text information about the last called method or property. |
| `LastErrorXml` | `LastErrorXml` | read-only | Provides XML-formatted information about the last called method or property. |
| `LastMethodSuccess` | `LastMethodSuccess` | read/write | Indicates the success or failure of the most recent method call: `true` means success, `false` means failure. |
| `VerboseLogging` | `VerboseLogging` | read/write | If set to `true`, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. |
| `Version` | `Version` | read-only | Version of the component/library, such as "10.1.0" |

## Member index

| Member | Kind | Signature |
|---|---|---|
| `AbortCurrent` | property, read/write | `AbortCurrent` |
| `CompressFile` | method | `var success = CompressFile(inFilename, destPath);` |
| `CompressStringToFile` | method | `var success = CompressStringToFile(inStr, charset, destPath);` |
| `UncompressFile` | method | `var success = UncompressFile(inFilename, destPath);` |
| `UncompressFileToString` | method | `var strVal = UncompressFileToString(zFilename, charset);` |
| `UnTarZ` | method | `var success = UnTarZ(zFilename, destDir, bNoAbsolute);` |

## Properties

### UnixCompress.AbortCurrent

`Chilkat 11.7.0 · js · UnixCompress · AbortCurrent · property · read/write · since 9.5.0.58`

```javascript
AbortCurrent
```

· `boolean`

When set to `true`, causes the currently running method to abort. Methods that always finish quickly (i.e.have no length file operations or network communications) are not affected. If no method is running, then this property is automatically reset to `false` when the next method is called. When the abort occurs, this property is reset to `false`. Both synchronous and asynchronous method calls can be aborted. (A synchronous method call could be aborted by setting this property from a separate thread.)

## Methods

### UnixCompress.CompressFile

`Chilkat 11.7.0 · js · UnixCompress · CompressFile · method`

```javascript
var success = CompressFile(inFilename, destPath);
```

· return: `boolean`; `true` for success, `false` for failure  
· inFilename: `string`  
· destPath: `string`

Compresses a file to create a UNIX compressed file (.Z). This compression uses the LZW (Lempel-Ziv-Welch) compression algorithm.

Returns true for success, false for failure.

### UnixCompress.CompressStringToFile

`Chilkat 11.7.0 · js · UnixCompress · CompressStringToFile · method`

```javascript
var success = CompressStringToFile(inStr, charset, destPath);
```

**Full documentation for this method (same in every language):** [List of Valid Charsets](https://www.chilkatsoft.com/ai-docs/v/11.7.0/articles/charsets_supported_by_chilkat.md)

· return: `boolean`; `true` for success, `false` for failure  
· inStr: `string`  
· charset: `string`  
· destPath: `string`

Unix compresses and creates a .Z file from string data. The `charset` specifies the character encoding used for the byte representation of the characters when compressed. The `charset` can be any one of a large number of character encodings, such as `utf-8`, `iso-8859-1`, `Windows-1252`, `ucs-2`, etc.

Returns true for success, false for failure.

### UnixCompress.UncompressFile

`Chilkat 11.7.0 · js · UnixCompress · UncompressFile · method`

```javascript
var success = UncompressFile(inFilename, destPath);
```

· return: `boolean`; `true` for success, `false` for failure  
· inFilename: `string`  
· destPath: `string`

Uncompresses a .Z file. (This compression uses the LZW (Lempel-Ziv-Welch) compression algorithm.)

Returns true for success, false for failure.

### UnixCompress.UncompressFileToString

`Chilkat 11.7.0 · js · UnixCompress · UncompressFileToString · method`

```javascript
var strVal = UncompressFileToString(zFilename, charset);
```

**Full documentation for this method (same in every language):** [List of Valid Charsets](https://www.chilkatsoft.com/ai-docs/v/11.7.0/articles/charsets_supported_by_chilkat.md)

· return: `string`  
· zFilename: `string`  
· charset: `string`

Uncompresses a .Z file that contains a text file. The contents of the text file are returned as a string. The character encoding of the text file is specified by `charset`. Typical charsets are `iso-8859-1`, `utf-8`, `windows-1252`, `shift_JIS`, `big5`, etc.

Returns `null` on failure

### UnixCompress.UnTarZ

`Chilkat 11.7.0 · js · UnixCompress · UnTarZ · method`

```javascript
var success = UnTarZ(zFilename, destDir, bNoAbsolute);
```

· return: `boolean`; `true` for success, `false` for failure  
· zFilename: `string`  
· destDir: `string`  
· bNoAbsolute: `boolean`

Unpacks a .tar.Z file. The decompress and untar occur in streaming mode. There are no temporary files and the memory footprint is constant (and small) while untarring.

Returns true for success, false for failure.

## Events and callbacks

This binding has no event callbacks.