Table of Contents Previous Chapter Review of Unix.

Review of Unix.

4 Review of Unix.

4.1 Major UNIX variants on campus.

4.2 Unix Variants

This diagram shows the "family tree" of the Unix operating system.

SunWorld online publishes a yearly comparison of Unix versions.

4.3 Files.

ls -l to see file types (left most character in listing)

4.4 Modes (octal)

4.4.1 Mode Examples

There are three sets of modes (as shown above). Each set is represented by:

Tabell 2: Mode examples 
-------------------------------------
Octal  Binary  chmod       umask       
               permission  permission  
-------------------------------------
0      000     ---         rwx         
1      001     --x         rw-         
2      010     -w-         r-x         
3      011     -wx         r--         
4      100     r--         -wx         
5      101     r-x         -w-         
6      110     rw-         --x         
7      111     rwx         ---         
-------------------------------------

4.4.2 Command Examples

# chmod 700 file1
# chmod 2755 file2
# chmod 4750 file3

4.5 Processes.

# ps -aux | egrep -v "^root|^lp|^daemon"
# alias pu "ps -aux | egrep '^\!:1|^USER'"
# pu yourname

4.6 fork() / exec()

Here is an diagram that shows how fork()/exec() work. This program shows how the calls are used in a C program.

4.7 BSD filesystem layout

Here is an example of the BSD file system layout.

4.8 System V filesystem layout

Here is an example of the System V.4 file system layout.

4.9 Related articles

4.10 Example Problems and Reading

 
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