1. June 1, 1999Customizing the UNIX Environment1 Introduction to UNIX G. Customizing the UNIX Environment

2. June 1, 1999Customizing the UNIX Environment2 Performance Objectives 1. Describe the purpose of "Dot" files 2. Add a path variable to the.cshrc file 3. Re-source a dot file (source) 4. Define basic Shell Variables (PATH, SHELL, TERM, HOME) 5. Define the minimal content for the.login File (stty, setenv) 6. View Your Environment (env, stty all) 7. List aliases. 8. Temporarily disable an alias (unalias). 9. Change C-shell features with toggles (noclobber, ignoreeof, notify)

3. June 1, 1999Customizing the UNIX Environment3 Customizing Your Environment “Dot” files define the environment. Usually in your home directory. The.login is executed only once at log in. The.cshrc is executed for each C-Shell. The.pinerc file defines the mail environment. The.forward file routes mail to another host.

4. June 1, 1999Customizing the UNIX Environment4 What happens when you log in? You enter a login name and password. If the default shell is /usr/bin/tcsh, the T-Shell is set as your command interpreter. The T-Shell executes the commands in your ~/.cshrc file or ~/.tcshrc file. Then the T-Shell executes the commands in your ~/.login file.

5. June 1, 1999Customizing the UNIX Environment5 Content of.cshrc A typical.cshrc file contains: è set path=(. ~/bin /usr/ucb /usr/bin /usr/local/bin) è set term=vt100 è set history=30 è set ignoreeof è alias rm rm -i è alias lo logout

6. June 1, 1999Customizing the UNIX Environment6 Content of.login A typical.login file contains: è stty erase ^H (tset -I -Q -e^H -k^U) è setenv EDITOR vi è setenv PRINTER lw

7. June 1, 1999Customizing the UNIX Environment7 Changing “dot” Files Templates are placed in new mode accounts Configuration changes made interactively are valid only for the current session. Changes made to.login or.cshrc are not active in the system until that file is "sourced": host% source.login

8. June 1, 1999Customizing the UNIX Environment8 Environment Commands setenv sets global environment variables: è setenv VARIABLE value stty sets terminal I/O characteristics: è stty option set defines predefined variables: è set variable=value alias redefines commands: è alias name “command list”

9. June 1, 1999Customizing the UNIX Environment9 Displaying Global Environment printenv displays values of global environment variables. host% printenv (environment of login session) HOME=/scc/users/chttspit SHELL=/bin/csh TERM=vt100 USER=chttspit PATH=.:/scc/users/chttspit/bin:/usr/ucb:/usr/bin:/usr/local/bin LOGNAME=chttspit PWD=/usr/local/scc/stts EDITOR=vi

10. June 1, 1999Customizing the UNIX Environment10 Display the Local Environment set displays C-Shell's local variables. host% set (environment "local" to current shell) cwd /usr/local/scc/stts history 30 ignoreeof (cannot use ^D to logout) noclobber (confirmation of file redirect overwrite) noglob (metacharacters * [] {} ? ~ not expanded) path (. /scc/users/chttspit/bin /usr/ucb /usr/bin … ) shell /bin/csh term vt100 user chttspit

11. June 1, 1999Customizing the UNIX Environment11 Display Terminal Characteristics Use stty to display terminal characteristics. host% stty speed 9600 baud; evenp erase = ^H -inpck imaxbel -tab crt Special Characters erase ^H kill ^U intr ^C eof ^D

12. June 1, 1999Customizing the UNIX Environment12 Displaying Aliases Use alias to display all aliases. host% alias lo logout rm rm -i Use unalias to deactivate an alias: host% unalias rm

13. June 1, 1999Customizing the UNIX Environment13 C Shell Toggles - noclobber Produces an error if è redirects (>) are made to existing files è appends (>>) are made to non-existing file Can be used interactively with set and unset Can be put into.login or.cshrc Presence can be viewed with set command

14. June 1, 1999Customizing the UNIX Environment14 C Shell Toggles ignoreeof -- Shell ignores EOF from terminals. Protects against accidentally killing a C shell by typing CTRL-D. noglob -- Inhibits filename substitution. Used in scripts once filenames are obtained and no further expansion is desired. notify -- Shell notifies you as jobs are completed, rather than waiting until a prompt.

15. June 1, 1999Customizing the UNIX Environment15 End of Module Complete Customizing the UNIX Environment Exercises