PPT Slide
More UNIX specifics
- Concept of standard input (stdin or file descriptor 0), standard output (stdout or file descriptor 1), and standard error (stderr or file descriptor 2)
- UNIX shell program interpret certain characters (metacharacters - chars with meanings other than their standard ASCII value)
- < and > use to re-direct standard input and output
- VERY useful abstraction; if programmer uses stdin and stdout then the program doesn’t require any specific input and output files!
- Pipe symbol (“|”) a shortcut for
who > who.out; sort < who.out
who | sort