How to password protect a gzip file?

The gzip command itself does not support password protection directly. However, you can achieve password protection by first compressing the file with gzip and then encrypting it using a tool like gpg. Here’s how you can do it:

Compress the file with gzip:
```
gzip file.txt
```
This will create a compressed file named file.txt.gz.
Encrypt the gzip file using gpg:
```
gpg -c file.txt.gz
```
This command will prompt you to enter a password. It will create an encrypted file named file.txt.gz.gpg.

To decrypt and unzip the file later, you would use:

Decrypt the file:
```
gpg file.txt.gz.gpg
```
You will be prompted to enter the password.
Unzip the decrypted file:
```
gunzip file.txt.gz
```

This process effectively password protects your gzip file.