Introduction to Linux Commands

Overview of Common Linux Shell Commands

What is a shell?

• User interface for running commands
• Interactive language

• Scripting language

  Shell command applications:

• Getting information
  • whoami – username
  • id – user ID and group ID
  • uname – operating system name
  • ps – running processes
  • top – resource usage
  • df – mounted file systems
  • man – reference manual
  • date – today’s date
• Navigating and working with files and directories
• Printing file and string contents
• Compression and archiving
  • tar – archive a set of files
  • zip – compress a set of files
  • unzip – extract files from a compressed zip archive
• Performing network operations
  • hostname – print hostname
  • ping – send packets to URL and print response
  • ifconfig – display or configure system network interfaces
  • curl – display contents of file at a URL
  • wget – download file from a URL
• Monitoring performance and status

Customizing View of File Content

• sort — Sort lines in a file, -r will do the same in the reverse
• uniq — Filter out repeated lines
• grep (“global regular expression print”) — Return lines in file matching pattern
• grep -i — makes grep search case-insensitive
• cut — Extracts a section from each line
• paste — Merge lines from different files