programs need a reference to a file they cnanot use the file name on each write operation
Standard File Descriptors
- stdin: standard input
- stdout: standard output
- stderr: standard error
- stdin is a file descriptor that is used to read input from the user
- stdout is a file descriptor that is used to write output to the user
- stderr is a file descriptor that is used to write error messages to the user
Pipes
Pipes : Examples
Pipes : xargs transfors stdin to command line args
The Filey Type
- regular file [-]
- directory [d]
- link [l]
- socket [s]
- pipe [p]
- block device [b]
- character dervice [C]
Defaukt Protection of a New File
$ umask 022
010
rwx
die umask Einstellung sort dafür, dass die Zugriffsrechte nach dem anlegen eines Directories vorhanden sind