How to use the command 'shar' (with examples)

The shar command, short for “shell archive”, is used to create a shell script that can extract files from itself when executed. It is commonly used for distributing collections of files and directories as a single, self-extracting archive.

Use case 1: Create a shell script that extracts files

Code:

shar --vanilla-operation path/to/file1 path/to/file2 ... > path/to/archive.sh

Motivation: This use case is useful when you want to distribute a set of files or directories as a single, self-extracting shell script. It allows the recipients to easily extract the contents without requiring additional tools.

Explanation:

• --vanilla-operation: This option specifies that the files should be extracted from the shell script when executed.
• path/to/file1 path/to/file2 ...: Specifies the files or directories to be included in the archive.
• > path/to/archive.sh: Redirects the output of the shar command to the specified file.

Example output: The archive.sh file will be created, containing the shell script and the specified files. When executed, it will extract the files to the current directory.

Use case 2: Compressing files in the archive

Code:

shar --compactor xz path/to/file1 path/to/file2 ... > path/to/archive.sh

Motivation: When distributing large archives, it can be beneficial to compress the files to reduce their size. This makes downloading and transferring the archive faster and more efficient.

Explanation:

• --compactor xz: Specifies that the files should be compressed using the XZ compression algorithm. Other options include gzip and bzip2.
• path/to/file1 path/to/file2 ...: Specifies the files or directories to be included in the archive.
• > path/to/archive.sh: Redirects the output of the shar command to the specified file.

Example output: The archive.sh file will be created, containing the compressed archive and the specified files. When executed, it will extract the files to the current directory.

Use case 3: Treating all files as binary

Code:

shar --uuencode path/to/file1 path/to/file2 ... > path/to/archive.sh

Motivation: Sometimes, it is necessary to treat all files as binary to ensure their integrity when extracting. This can be useful for files that contain non-textual data, such as images or executables.

Explanation:

• --uuencode: Specifies that all files should be encoded using the uuencode algorithm to ensure their integrity when extracting.
• path/to/file1 path/to/file2 ...: Specifies the files or directories to be included in the archive.
• > path/to/archive.sh: Redirects the output of the shar command to the specified file.

Example output: The archive.sh file will be created, containing the uuencode encoded files and the specified files. When executed, it will extract the files to the current directory.

Use case 4: Treating all files as text

Code:

shar --text-files path/to/file1 path/to/file2 ... > path/to/archive.sh

Motivation: In some cases, it may be necessary to treat all files as text to preserve their formatting and ensure compatibility with text editors and viewers.

Explanation:

• --text-files: Specifies that all files should be treated as text, meaning they won’t be encoded using uuencode.
• path/to/file1 path/to/file2 ...: Specifies the files or directories to be included in the archive.
• > path/to/archive.sh: Redirects the output of the shar command to the specified file.

Example output: The archive.sh file will be created, containing the specified files. When executed, it will extract the files to the current directory.

Use case 5: Including a name and cut mark in the header comment

Code:

shar --archive-name "My files" --cut-mark path/to/file1 path/to/file2 ... > path/to/archive.sh

Motivation: Including a name and cut mark in the header comment of the archive can provide additional information and make it easier for recipients to identify the contents.

Explanation:

• --archive-name "My files": Specifies the name to be included in the header comment of the archive.
• --cut-mark: Specifies that a cut mark should be added to the header comment, indicating the start of the archive contents.
• path/to/file1 path/to/file2 ...: Specifies the files or directories to be included in the archive.
• > path/to/archive.sh: Redirects the output of the shar command to the specified file.

Example output: The archive.sh file will be created, containing the specified files. The header comment will include the name “My files” and a cut mark indicating the start of the archive contents.

Conclusion:

The shar command is a versatile tool for creating self-extracting shell archives. By using different options and arguments, you can customize the behavior of the command to suit your needs. Whether you want to compress files, treat them as text or binary, or add additional metadata, the shar command provides the flexibility to do so.