1. John Carelli, Instructor Kutztown University carelli@kutztown.edu

2. Command line interpreter/user interface
Unix Shell
Command line interpreter/user interface
Common Shells:
Bourne – sh
Korn – ksh
C shell – csh
Bourne Again Shell – bash
Debian Almquist Shell (dash)
TC Shell (tcsh)
Z Shell (zsh)

3. HOME
PATH
PS1 / prompt
USER
SHELL
TERM
CDPATH
modify settings in .bash_profile
hidden file: use ‘ls –a’ in your home directory to see it

4. env
history
set +/-o (turn shell options on/off)
ignoreeof
prevent (accidental) exit on Cntl-D
noclobber
prevent (over)writing existing file
set –o (or +o) to see current options
cdpath
filec
enable filename completion (tsh)

5. […] File substitution wildcard (any char. in [])
 > Output redirection
 >> Output redirection, append
 < Input redirection
 | Pipe
 * File substitution wildcard (zero or more)
 ? File substitution wildcard (one char.)
[…] File substitution wildcard (any char. in [])
`command` Command substitution
; Separate commands

6. Redirection Pipes Standard input Standard output Standard error
/dev/null (null device)
ex: output.cpp
Pipes
ls /bin | grep sh

7. [] any character in the bracket ^ beginning of string $ end of string
? Single character
* 0 or more characters
[] any character in the bracket
^ beginning of string
$ end of string
ls /bin | grep sh$

8. Command Substitution Single quotes (back-tics) spawns a subshell
output of subshell command replaces “back-quoted” item
echo `date`
$() – newer syntax (bash)
echo $(date)
More history:
!! is last command
Cntl-P
emacs mode (bash default)
set –o emacs
esc-K
vi mode
set –o vi

9. Shell Script: an executable (text) file that contains shell commands.
When the shell script is run, the commands in it get executed
#!<shell_path>
Must be executable!
# comments
Environment variables
Local/Global variables
export command
ex: firstscript

10. cd, ls, pwd, echo, time, umask, …
help (bash built-ins)