How do I Zip/Unzip on the Unix Command Line

Zipping and unzipping files is a fundamental practice in Unix/Linux systems for file compression and archiving. We compress files to save disk space and bundle multiple files into a single archive for easier transfer and storage.

When working with compressed archives, understanding both compression and extraction commands is essential for effective file management in Unix environments.

Installing zip and unzip Commands

First, ensure that the zip and unzip utilities are installed on your system:

sudo apt install zip unzip

Basic zip and unzip Operations

Let's start with creating some sample files to demonstrate the compression process:

touch 1.txt 2.txt 3.txt 4.txt
ls

1.txt  2.txt  3.txt  4.txt

Now compress all text files into a single archive named all.zip:

zip all *.txt

  adding: 1.txt (stored 0%)
  adding: 2.txt (stored 0%)
  adding: 3.txt (stored 0%)
  adding: 4.txt (stored 0%)

The archive all.zip is now created. To extract the files, use the unzip command:

rm *.txt
unzip all.zip

Archive:  all.zip
  extracting: 1.txt
  extracting: 2.txt
  extracting: 3.txt
  extracting: 4.txt

Extract to Target Directory

To avoid cluttering the current directory, extract files to a specific target directory using the -d option:

unzip -q all.zip -d new-all
ls new-all/

1.txt  2.txt  3.txt  4.txt

The -q flag suppresses the verbose output during extraction.

Exclude Files During Compression

To exclude specific files from compression, use the -x option:

zip all 1.txt 2.txt 3.txt -x 4.txt

updating: 1.txt (stored 0%)
updating: 2.txt (stored 0%)
updating: 3.txt (stored 0%)

Verify the exclusion by extracting to a new directory:

unzip -q all.zip -d excluded-demo
ls excluded-demo/

1.txt  2.txt  3.txt

List Archive Contents

To view the contents of a zip archive without extracting it, use the -l option:

unzip -l all.zip

Archive:  all.zip
  Length      Date    Time    Name
---------  ---------- -----   ----
        0  2016-02-11 22:25   1.txt
        0  2016-02-11 22:25   2.txt
        0  2016-02-11 22:25   3.txt
---------                     -------
        0                     3 files

Password Protection

Create password-protected archives using the -e (encrypt) and -r (recursive) options:

zip -e -r password-protected new-all/

Enter password:
Verify password:
  adding: new-all/ (stored 0%)
  adding: new-all/1.txt (stored 0%)
  adding: new-all/2.txt (stored 0%)
  adding: new-all/3.txt (stored 0%)

When extracting password-protected archives, you'll be prompted for the password:

unzip password-protected.zip

Archive:  password-protected.zip
[password-protected.zip] new-all/1.txt password:
  extracting: new-all/1.txt

Common zip and unzip Options

Conclusion

The zip and unzip commands provide essential file compression and extraction capabilities in Unix systems. These tools support various options including password protection, selective file exclusion, and directory-specific extraction, making them versatile for different archiving scenarios.