Computer History Notes - Herong's Tutorial Notes - v3.13, by Herong Yang
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
2002 - .NET Framework Developed by Microsoft
1995 - PHP: Hypertext Preprocessor Created by Rasmus Lerdorf
1995 - Java Language Developed by Sun Microsystems
1991 - WWW (World Wide Web) Developed by Tim Berners-Lee
1991 - Gopher Protocol Created by a University of Minnesota Team
1984 - X Window System Developed a MIT Team
1984 - Macintosh Developed by Apple Inc.
1983 - "Sendmail" Mail Transfer Agent Developed by Eric Allman
1979 - The Tcsh (TENEX C Shell) Developed by Ken Greer
1978 - Bash (Bourne-Again Shell) Developed by Brian Fox
►1978 - The C Shell Developed by Bill Joy
Command Line History Substitution
Command Line Alias Substitution
Command Line Input and Output Redirection
►Command Line Variable Substitution
".cshrc" - C Shell Script File and
1977 - The Bourne Shell Developed by Stephen Bourne
1977 - Apple II Designed by Steve Jobs and Steve Wozniak
1976 - vi Text Editor Developed by Bill Joy
1974 - Internet by Vinton Cerf
1972 - C Language Developed by Dennis Ritchie
1971 - FTP Protocol Created by Abhay Bhushan
1970 - UNIX Operating System Developed by AT&T Bell Labs