Documentation is a great way to learn about installed utilities.
The /usr/share/doc/ directory contains README files and other documents for installed commands.
man: It is a command to access reference manual pages for all installed commands. Usage man <command_name>.
info: It is a command to access full-detailed information pages for all installed commands. Usage info <command_name>.
Compression
Compression reduces file sizes.
Three popular compression commands are: gzip, bzip2 & xz.
Compress: To compress run commands like so: compression utility [options] file_name.
Decompress: To decompress include the -d option: <compression_utility> -d <compressed_file_name>.
gzip also supports the -r option to compress all files in a directory.
Archive
In computing, an archive file is a computer file that is composed of one or more files along with metadata. Archive files are used to compress files in order to use less storage space.
zip & tar are two archiving utilities that package multiple files into a single archive file.
zip - Archives & compresses files
Archive: zip <archive_name>.zip [file1] [file2]... Use the -r option for directories.
Extract:unzip <archive_name>.zip.
tar
Only archives files by default but has options to utilize compression utilities. Unlike zip, it preserves Unix file attributes like file permissions.
Archive:tar -cf <archive_name>.tar files or directory.
Extract:tar -xf <archive_name>.tar.
Add options -z, -j, or -J to compress via gzip, bzip2, or xz respectively.
Networking
curl or wget: Interacts with a webpage of file hosted online.
ping : Checks connectivity between two devices on the same network.