How to use the command `zcat` (with examples)
The zcat command is used to print the contents of gzip compressed files to the standard output. It is a convenient way to view the contents of compressed files without having to first decompress them. Additionally, it can also provide information about the compression details of a gzip file.
Use case 1: Print the uncompressed contents of a gzipped file to stdout
Code:
zcat file.txt.gz
Motivation:
Sometimes we may want to quickly view the contents of a gzipped file without having to go through the process of decompressing it. In such cases, using zcat allows us to directly view the uncompressed contents of the file.
Explanation:
zcat: The command itself used to print the contents of a gzip compressed file.file.txt.gz: The name of the gzipped file we want to view the contents of. This file should already exist in the current directory.
Example output:
If the file file.txt.gz contains the text “Hello, World!”, running the above command will print the following output to the terminal:
Hello, World!
Use case 2: Print compression details of a gzipped file to stdout
Code:
zcat -l file.txt.gz
Motivation:
Sometimes we may want to know more about the compression details of a gzip file, such as the compression ratio and uncompressed size. By using zcat with the -l flag, we can obtain this information without having to decompress the file.
Explanation:
zcat: The command itself used to print the compression details of a gzip compressed file.-l: The flag to specify that we want to print the compression details.file.txt.gz: The name of the gzipped file we want to retrieve the compression details from. This file should already exist in the current directory.
Example output:
If the file file.txt.gz has a compression ratio of 0.5 and an uncompressed size of 100 bytes, running the above command will print the following output to the terminal:
compressed uncompressed ratio uncompressed_name
38 76 0.50 file.txt
Conclusion:
The zcat command is a handy tool for quickly viewing the contents of gzip compressed files without needing to decompress them. Additionally, it provides information about compression details, which can be useful for analyzing the effectiveness of compression and the uncompressed size of the file.
