Linux and UNIX Systems Configuration Help, How To, Tutorial and Basic Information

1. whatis

Command whatis Searches for whole words in the database whatis (see command apropos). Syntax whatis keyword Options no Description whatis command displays the result of search whole words ...

2. wc

Command wc Displays the number of bytes, words and lines found in the file. Syntax wc [options] [files] Options -c displays only the number of bytes. -w only shows the number of words. -l ...

3. uptime

Command uptime Displays the time of continuous operation of the system. Syntax uptime Options no Description uptime utility displays the current time, time of continuous operation of the system, ...

4. uname

Command uname Displays system information, such as the type of machine and operating system. Syntax uname [options] Options -a displays all the information. -m displays the type of equipment ...

5. unalias

Command unalias Eliminates the abbreviation as defined previously by using the alias. Syntax unalias abbreviation Options no Description command unalias removes the abbreviation as defined ...

6. touch

Command touch Changes the timestamp of file. Syntax touch [options] files Options -c prescribes not to touch the file if it does not exist. -d time, using the specified time. -r file uses a timestamp ...

7. top

Command top Displays a list of currently executing processes, ordered by the percentage use of CPU time. Syntax top [q] [d interval] Options q requires top performance with the highest possible ...

8. tar

Command tar Creates archive files or extract files from archives. Syntax tar [options] file_or_directory Options -c creates a new archive. -d compares the files from the archive files from the ...

9. tail

Command tail Displays the last few lines of the file. Syntax tail [options] file Options -N (where N - number) displays the last N lines. -n N (where N - number) displays the last N lines. -f ...

10. rmdir

Command rmdir Deletes the specified directory (if it is empty). Syntax rmdir [options] directory Options -p remove all parent directories which become empty. Description The command rmdir ...

11. rm

Command rm Removes one or more files. Syntax rm [options] files Options -f deletes files without asking. -i asks for confirmation before deleting files. -r recursively deletes files in all subdirectories ...

12. pwd

Command pwd Prints the current working directory. Syntax pwd Options No Description The command pwd prints the current working directory. It is a built-in command of Bash.  ...

13. pstree

Command pstree Displays all running processes in a tree. Syntax pstree [options] [process_id] Options -a displays the command line arguments. -c does not compress the subtrees. -l displays a long ...

14. ps

Command ps Displays the status of processes (programs) running in the system. Syntax ps [options] Options Note that unlike other commands ps command options do not have a prefix "-". a display ...

15. passwd

Command passwd Changes the password. Syntax passwd [username] Options No Description The passwd command changes your password. It asks for old password, and then the new password. If you are ...

16. mv

Command mv Renames files and directories or move them from one directory to another. Syntax mv [options] source destination Options -b creates backup copies of files that are moved or renamed. ...

17. more

Command more Performs view text files. Syntax more [options] file_names Options +N (where N - number) displays the file, starting at the specified line number. +/pattern begins with a display ...

18. man

Command man Print page operational manual (also called man-pages). Syntax man [options] [section] command Options -C conf_file indicates configuration file man (by default /etc/man.config). -p ...

19. mkdir

Command mkdir Creates a directory. Syntax mkdir [options] directory_names Options -m access appoints new directory specified access rights. -p creates parent directories if they do not exist. ...

20. ls

Command ls Prints the contents of the directory. Syntax ls [options] [directory-names] Options -a displays all files, including those with names starting with a dot (.). -b displays unprintable ...