Some Linux Commands

Date and time

• date (show system date)
• cal 9 1751( show calendar)
• date mmddhhmmssyy ( set date & time)
• date 12051145302008

Find

• find / -name sam.txt (find a file)
• find / -iname sam.txt (search with capital & small)
• find / -size 1 mb (find files with 1 mb size)
• find / -size +1mb (find files > then 1 mb)
• find / -size -1 mb (find files <then 1 mb)
• find / -usr marc (find  user marc,s files )
• find / home –user marc (find user march in home )
• stat /data/sam.txt (displays file properties)
• touch /data/sam.txt (update the time)
• touch logitech
• find / -atime +10
• find / – atime -10
• find / -mtime +10
• find / -mtime -10
• find / -name india.txt –not –user mann
• find / -name kashmir.txt –not user root
• find / -name india.txt –not –size -10mb
• find / -name india.txt –and –user mann –not –size +10mb

Linux – File And directories

• rm abc  (can remove a file)
• mkdir abc (create a directory)
• rmdir abc (remove an empty directory)
• rm –r abc (delete directory recursively)
• mkdir /data (create a directory)
• mkdir /data/abc (create sub directory)
• pwd (print working directory)
• cd /data ( change the directory)
• cd (change to home directory)
• cd / (change to / directory)
• cd .. (come back one directory)
• cd – ( back to previous directory)
• tree /root ( to display directory structure)
• rm –rf  abc ( to delete a directory forcefully & recursively)
• ls (list of files and folders in current directory)
• ls –l (long listing of files & folders)
• ls –a (list all with hidden files & folders)
• ls /  (list files & folders )
• ls /abc/xyz (will list subdirectories)
• cp –rvf /abc/xyz  (copy recursively)
• ls *.txt (list .txt files)
• history (displays last inserted commands)
• !10 (run number 10th command)
• !cal (run last command started with cal)
• history –c (Clear all history)
• man/info date (manual files)
• makewhatis (creates what is database)
• whatis cal (displays use of cal command)
• cal > abc ( send output of cal  to file abc)
• date >> abc (append to abc file)
• more sales.txt (displays page contents page wise)
• history | more (displays history page wise)
• history | less (———— can up and down)
• history | tail -20 ( displays last 20 inserted lines)
• History > history.txt (send history to a file)
• tr ‘a-d ‘ ‘A-D’ < sam.txt ( display small to capital)
• tr ‘A-D ‘a-d’ < sam.txt (displays capital to small)

Text Editor in Linux

• The vi or vim editor can be used to create edit a file in Linux operating system. And it has three modes.
• 1) cmd mode : File editing commands like copy, paste, search, replace, delete
• 2)Insert mode: It can be used to insert text or delete text in a file.
• 3)ex mode : Exit mode is used to save the text in a file and can be used to quit from a file.
•        vi abc           ( can  create a file)

Press  I                     ( to insert text in a file)

Press  esc                (to come back to cmd mode)

Press  esc                (to ex mode)

Press  :w                  (to save text in a file)

Press  :q                  (to quit from a file)

Press  :wq              (to save & quit from a file)

Press  :q!                to forcefully quit without saving

Press  :wq!             To forcefully quit & save a file

Press  :u                  to undo last changes

Press  :abc             (to search abc from a file)

Press   yy               to copy a line

Press  p                   to paste

Press  dd                to delete a line

Press  5 dd            to delete 5 lines

Press  5yy             to copy 5 lines

Press  ctrl + r       to redo

Press   o                  to insert a line down

Press  shift + o     to insert a line at up

Press shift + g      to insert a cursor at end of the last line

Press shift + m    to put  cursor in middle of  screen

Press shift+h       to put cursor top of the screen

Press yw                to copy a word

Press yc                 to copy a character

Press  dw               to delete a particular word

Press 5+ dw          to delete no of words

• cat > abc (create a file ctlr+d to save)
• cat abc  (displays the contents of a file)
• cp /abc  /root/abc (copy a file)
• mv abc appin (rename a command)
• mv appin /root (can move a file)
• cat >> abc (append to a file)