Almost everything in Unix is a file!

• Regular files
• Directories - Directories are just files listing a set of files
• Symbolic links - Files referring to the name of another file
• Devices and peripherals - Read and write from devices as with regular files
• Pipes - Used to cascade programs.

  cat *.log | grep error

• Sockets - Inter process communication

 

File names

File name features since the beginning of Unix

• File names in linux are Case sensitive
• File names in linux has No obvious length limit
• File names in linux can contain any character (including whitespace, except /). File types stored in the file (“magic numbers”). File name extensions not needed and not interpreted. Just used for user convenience.
• File name examples:

  README			.bashrc			Windows Buglist
  index.htm		index.html		index.html.old
  

 

File paths

A path is a sequence of nested directories with a file or directory at the end, separated by the / character

• Relative path:

  $ documents/files/my_filwe.txt
  

  Relative to the current directory
• Absolute path:

  $ /home/pc_name/dir/file_abc.txt
  

• root directory.

  $ /
  

  Start of absolute paths for all files on the system (even for files on removable devices or network shared).

 

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