Overview
Command usage idea Permission File directory Shell archieve search System info Process Schedule help Maths User Hardware Useful command Others Network
1: Command usage idea
| ls command usage | ls -l * ( to display all the directory along with its content ) | |
| file command usage | File * ( to display type of all the child of current directory ) | |
| File *.jar ( to display info about the jar files only ) | ||
| File * | grep link |
2: Permission
| change permission on a file | chmod | |
| change group of a file | chgrp | |
| change owner of a file( only super user ) | chown |
3: File
| used to view the large file | More & less | it is do scroll bar task of windows |
| pg | ||
| display first or last given no. Of lines of file | Head & tail | |
| display content of file | cat | |
| sort the file content | sort | |
| remove duplicate line of given file | uniq | |
| create a empty file in given name | touch | c |
| display content type of a file | file | |
| get only file without path | basename | |
| mv | ||
| rm | ||
| copy file | cp |
4: directory
| present working directory | pwd | |
| change directory | cd | |
| list directory & files | ls | a(also display hidden files ), i ( i-node no. ), p ( display directory name with slash ), R ( recursively display of sub direcory ) |
| create directory | mkdir | |
| delete directory | rmdir |
5: Shell
| change the default login shell | chsh | ||
| list the command history of shell | fc | l | |
| recently used commands | history | ||
| I am not clear | stty | ||
| to record current session in a file ( it will useful to give another developer wht to do ) | Script & exit | -a | |
| to lanuch another command | exec | ||
| config network devices | ifconfig | ||
| to reflect configuration file changes to current session without logout | source | ||
| shell sleep for given seconds | sleep | ||
| to terminate shell script execution | exit | ||
| make is command to create binary file ( like ant ) | make | ||
| always return true used in shell scripting (Built in command in shell itself . No binary file for this command) | 1 | ||
| always return true used in shell scripting (Built in command in shell itself . No binary file for this command) | 0 | ||
| case | |||
| while | |||
| for | |||
| if | |||
| Built in command in shell itself for test numeric, string and file comparision . No binary file for this command in system. | test | ||
| it used to identity shell built in commands like true, false, test, [, etc. type itself built in command | type | ex: type test, type true | |
| it is used to define a function | declare | f | |
| null command ( colon ) | : | ||
| execute shell script file ( dot ) | . | ||
| change directory to home directory ( note. No argument ) | cd | ||
| echo | |||
| eval | |||
| exec | |||
| exit the current shell | exit | ||
| to make avilable a variable for sub shell | export | ||
| pwd | |||
| read | |||
| set | |||
| trap | |||
| all the user defined alias stored in .bashrc file for bash shell | alias | ||
| test command's alternative | [ | ||
| truncate the file | >or : > | ||
| continuation for command line | \ | ||
| input rediirect from a file | < | ||
| redirect output and append if a file alreay | >> | ||
| redirect output and truncate if file already | > | ||
| recirect output of a command to ANOTHER COMMAND | |||
| to run a command in background mode | & | ||
| current process id | $$ | ||
| recent background process id | $! | ||
| recent process or command's exit status | $? | ||
| diplay only GLOBAL the environment variable | env | ||
| diplay only GLOBAL the environment variable | printenv | ||
| diplay all LOCAL as well as ENVIRONMENT (exported ) the environment variable | set | ||
| Make unavailable variable name and any user defined function | unset | ||
| diplay only GLOBAL the environment variable | env |
6: archieve
| make many file to single file | tar | c, f |
| compress and expand utility | zcat | |
| data dumper | dd | |
| compress while creating archieve file | compress | |
| uncompress while extracting archieve file | uncompress | |
| it is best compare with compress command. It take a tar file to compress | gzip | |
| it is lates of gzip | bzip2 | |
| to un compress a compressed file by gzip | gunzip | |
| it has both create and compress the archieve file. It useful to if file used in window os | zip |
7: search
| search a given file in computer using metadata but not by content of file( it check all dir/subdirecory ) | find | |
| quick search in system database for given file ( check only PATH value ) | locate | |
| search a line in file for given regular expression | grep | I,v,n,c |
| extended grep | egrep | |
| used to search for given TEXT for given files | fgrep | I,v,n |
| translate SINGLE charactors usually, special \n, \t, or any alphanumic charactor | tr | |
| used to find/replace/search MORE THAN One Charactor | sed | e |
| another popular stream editor like sed | awk/gawk | |
| find printable string in a file | strings |
8: System info
| to list name of installed package, it is debian specific | dpkg -l | RedHad and suse are mostly used in industries |
| who are all logged in, administrative command | Who & W | |
| who are all logged in, administrative command | finger | |
| display the current user | whoami | |
| to log off from system | logout | |
| to know how long a given command executed | time |
9: Process
| to list name of process | ps | e, f, a, u, x | forest |
| to send ANY singal to running process | kill | l | |
| display the process in tree structure | pstree | ||
| display top 5 proecess | top | ||
| show virutual memory statuss | vmstat | ||
| to bring a background process to forgroound | fg | ||
| to move a foreground process to background | bg | ||
| to run any process in background | [command]& | ||
| size of memory segment of a process | size | ||
| usage of shared library | ldd | ||
| i dont know | ulimit |
10: Schedule
| used to edit etc/crontab file, | crontab |
| it is process thread, check periodically etc/crontab file | cron |
| run a task at specfic (run only one) time, it is deamon process | atd |
11: help
| to know path of a command (that is existence of command in os ) | which | which ls/cd/mv/etc. |
| to know all path of a command ( binary, source, man page ) | whereis | s,b,m |
| to know the command information | apropos | |
| short version of a command | info | |
| Display detail help content of a command | man | -k |
12: Maths
| desktop calucator ( like our calc ) | dc |
| more complex float or double artimetic operation | bc |
| expression evaluation | expr |
| open GUI calculator | xcalc |
13: User
| change the password | passwd | vmc server install in linux , and use client in window machine. |
| id of current user | id | it just a mechanism to manage the users |
| to list name of groups in system | groups | it just a mechanism to manage the users |
14: Hardware
| disk free information of each disk or partition ( mounted with file system ) | df | h |
| size of current folder / file | du -hs | |
| to check the file system for inconsistency( any dirty ) | fsck | |
| scandisk | ||
| display the OS name, processor, mother board architecure, etc, | uname | o, hardware-platform, p,a, all |
| give name of computer | hostname | |
| mount a file system under unix file system. It can be any file system |
We should mount any file system like floppy, cd, pen drive, other hard disk partition, before to
To use. Now a days it happed on single click instead running commands | mount | |
| un mount a file system under unix file system | umount | |
| display x widget package | xdpyinfo | |
| | dd | |
| | mksf | |
| | newfs | |
| | dcopy | |
| it show main memory and swap memory size of system | free | |
15: Useful command
| find delete files | find . -type f -name "FILE-TO-FIND" -exec rm -f {} \; |
16: Others
| translate SINGLE charactors usually, special \n, \t, or any alphanumic charactor | tr |
| screen shot | xv |
| screen shot | xwd |
| screen shot | gimp |
| screen shot | xeyes |
17: Network
| email utility | |
| email utility | mailx |
| utility to convert rpm package to deb package | alien |
| used by oracle installation | libaio1 |