Comparison of shells

Initially, the UNIX OS used a shell program called Bourne Shell. Then eventually, many more shell programs were developed for different flavors of UNIX. The following is brief information about different shells:

• Sh—Bourne Shell
• Csh—C Shell
• Ksh—Korn Shell
• Tcsh—enhanced C Shell
• Bash—GNU Bourne Again Shell
• Zsh—extension to Bash, Ksh, and Tcsh
• Pdksh—extension to KSH

A brief comparison of various shells is presented in the following table:

What we see here is that, generally, the syntax of all these shells is 95% similar. In this book, we are going to follow Bash shell programming.