Command Line Variable Substitution

This section provides a quick introduction of C shell command line variable substitution.

C Shell Command Line Variable Substitution: Replaces shell variables with their values.

Shell variables can be defined with the "set" command. For example, the following command defines a variable of "java home" with value of "/usr/local/lib/jdk1.1.1":

%set java home=/usr/local/lib/jdk1.1.1

Variable substitution uses the "$" character to identify user defined variable names and other built-in variables as listed below:

Examples of C shell command line input and output redirection:

>csh
%set java home=/usr/local/lib/jdk1.1.1
%echo $java home
/usr/local/lib/jdk1.1.1
%$java home/bin/java -version
java version "sbb:05/19/97-22:33"
%csh
%echo $shlvl
3
%echo $java home
java home: Undefined variable.
%exit
exit
%echo $?java home
1

Table of Contents

 About This Book

 1957 - FORTRAN Language Developed by IBM

 1970 - UNIX Operating System Developed by AT&T Bell Labs

 1971 - FTP Protocol Created by Abhay Bhushan

 1972 - C Language Developed by Dennis Ritchie

 1976 - vi Text Editor Developed by Bill Joy

 1977 - Apple II Designed by Steve Jobs and Steve Wozniak

 1977 - The Bourne Shell Developed by Stephen Bourne

1978 - The C Shell Developed by Bill Joy

 What Is the C Shell?

 C Shell Command Line

 Command Line History Substitution

 Command Line Alias Substitution

 Command Line Input and Output Redirection

Command Line Variable Substitution

 C Shell Command Line Examples

 ".cshrc" - C Shell Script File and

 1978 - Bash (Bourne-Again Shell) Developed by Brian Fox

 1979 - The Tcsh (TENEX C Shell) Developed by Ken Greer

 1983 - "Sendmail" Mail Transfer Agent Developed by Eric Allman

 1984 - Macintosh Developed by Apple Inc.

 1984 - X Window System Developed a MIT Team

 1991 - WWW (World Wide Web) Developed by Tim Berners-Lee

 1991 - Gopher Protocol Created by a University of Minnesota Team

 1995 - Java Language Developed by Sun Microsystems

 1995 - PHP: Hypertext Preprocessor Created by Rasmus Lerdorf

 2002 - .NET Framework Developed by Microsoft

 References

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