Unix Tutorial 8 : Shell scripting basics

Shells read configuration files on multiple circumstances that differ depending on the shell. These files usually contain commands for that  particular shell and are executed when loaded; they are usually used to set important variables that are used to find executables, like $PATH, and others that control the behavior and appearance of the shell.
  • The Bourne Shell (sh): This was one of the first shell programs that came with Unix and is also the most widely used one. It was developed by Stephen Bourne.  The ~/.profile file is used as a configuration file for sh. This is also the standard shell used for scripting.
  • The C Shell (csh): The C-Shell was developed by Bill Joy, modeled on the C programming language. It was intended to improve interactivity with features such as listing the command history and editing commands. The ~/.cshrc and the ~/.login files are used as configuration files by csh.
  • The Bourne Again Shell (bash): The bash shell was developed for the GNU project as a replacement for sh. The basic features of bash are copied from sh, and also adds some of the interactivity features from csh.  he ~/.bashrc and the ~/.profile files are used as configuration files by bash.

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