Presentation on theme: "Linux Workshop Session 1 Khadka, Santosh and Panthi, Sanjeeb Computer Science Department Lamar Univers Lamar Univers ity."— Presentation transcript:
Linux Workshop Session 1 Khadka, Santosh and Panthi, Sanjeeb Computer Science Department Lamar Univers Lamar Univers ity
What is covered? Working with files Working with directories Some basic commands Process related commands Working with vi editor Brief Introduction to Nano Editor
Login ! Galaxy Account can be used to access all the Linux machines in the lab 208, both locally and remotely To access locally, go to the any machines in 208 and use your username and password to login. To access remotely, use any secure shell (ssh) software. Example puTTY. Open a terminal by right clicking on your desktop. Type pwd -> shows the current working directory. You are in your home directory.
Tools Required for Remote Access ssh client - Example: putty for Windows platform sftp client - Example: WinScp for Windows platform remote sftp compatible editor - Example: jEdit for platform that supports java
Working with files To list all the files and/or folders in a current directory by default. ls [option]… [file]… Options: -a: to list all files -l: to list in long format showing file attributes and permission --author : gives the author name of the files. Better use with the combination of –l. File: Default is current working directory.
Working with files vi -opens a file to edit if exist, otherwise creates new file to edit ls - lists contents in current directory ls /etc - lists contents in directory /etc ls -a - this will list all file including those beginning with the'.' that would normally be hidden from view. Output redirection - Copies the output to some other file. Example: ls –l > filename (overwritten) ls –l >> filename (appended)
ls -l - this gives a long listing showing file attributes and file permissions. drwxrwxr-x 6 santoshk santoshk 4096 Sep 14 11:39 test -rw-rw-r-- 1 santoshk santoshk 140 Nov 17 09:08 test1.c cat - displays the content of the file - example: cat filename - cat –n filename (-n option for giving the line number)d cp cp - copy the content of the file - example: cp sourcefile.txt destnationfile.txt (source file is not deleted/modified) Working with files
scriptscript - to make script file - r - records everything printed on your screen. The record is recorded to the filename specified. - starts scripting, once done, type in +d to end scripting Example: script filename - makes a script file with the given filename script -a filename - append the session record to filename, rather than overwrite it mv mv - example: mv sourcefile.txt destiantionfile.txt (the sourcefile file is deleted) Working with files
tar - create archives and add or extract files tar –cvf output.tar inputfile Example: tar –cvf aos.tar AOS restore a tar file -tar -xvf inputfile.tar -.tar file is not compressed by itself. It just bundles the list of files in one folder. -add -z option to create a compressed tar file Example: tar -cvzf file.tar.gz Working with files
.gzip – compress the files Example gzip.gunzip –decompress the file Example gunzip Working with files
wc - counts the number of lines,words and bytes in the file - example: wc –l filename head - outputs the first part of the file - prints the first 10 lines by default - example: head filename head -n count filename tail - outputs the last part of the file. - example: tail mylist.cpp Working with files
lpr - print command - command: lpr -p printername filename Example: lpr -p lab208Printer -#2 file1.txt file2.txt (this will print two copies of file1.txt and file2.txt) Note: This is not available at present. Working with files
cd - changes the directory - example: cd mkdir - creates a directory under the current working directory. - example: mkdir rmdir - remove files - example: rmdir (for empty directory) rmdir –rf directoryname (recursive deletion with force) Working with directories
Working with files contd.. Absolute path: start with / (root) to go specific directory regardless of where you are now. Relative path : start with the current directory to go specific directory. Example: If, pwd: /home/myfolder then to go /home/myfolder/c++ Absolute path : cd /home/myfolder/c++ Relative path : cd c++
man -man - help manual - example: man keyword - press to view the next page - press to view next line - type “q” exit date - display or change the date - example: date --date =‘2 days ago’ date --set=“2009-9-4 11:59” date '+DATE: %m/%d/%y%n TIME:%H:%M:%S' DATE: 02/08/01 TIME:16:44:55 A few basic commands
-chmod - used to change the access permission - used to set file permissions to owner, group, and other -rw-rw-r-- 1 santoshk santoshk 140 Nov 17 09:08 test1.c - r = 4, w = 2, x = 1 - example: chmod 444 mylist clear - clear the screen grep - search the file for the specific text - example: grep string filname A few basic commands
hostname - displays or set the system name - example: hostname [name] - with no arguments prints the current host name. - with arguments sets the current host name to the specified string. more - display output one screen at a time - related command: less quota - display disk usage and limits - related command: du, df du –estimate the file space uses df – disk space uses (amount of disk space available) A few basic commands
ps - gives information about the running processes - example: ps -ef ps -fu username kill - sends a signal to a process to kill (ends the running process) - example: kill -9 pid exit - exit from the shell. If there are suspended jobs one cannot exit from the shell, so kill the processes using the kill command. Process related commands
vi filename esc - to enter vi command mode h: moves the cursor one character left (l right) j :moves the cursor one character down (k up) u :undo the last changes in the file x :deletes the character under the cursor d^: deletes all the characters from current cursor to beginning of the line d$ :deletes all the characters from current cursor to end of the line dw: deletes one word from the cursor. Brief Introduction to vi Editor
Insert text Enter input mode and: i a - insert text before ('i') or after ('a') the current character I A - insert text at beginning ('I') or end ('A') of current line o O - open new blank line after ('o') or before ('O') current line r R - replace one(‘r’) or more character (‘R’) by overwriting Brief Introduction to vi Editor contd..
Brief Introduction to vi Editor Exiting and Saving - Press esc and type :q to quit :wq or ZZ to save and quit :q! to quit without saving (!= Forcefully) :w to save the file :w filename to save current file under name filename Copy and Paste text nyy or nY - 'copies' n number of line p P - insert the contents of the paste buffer [ after / before ] the current line/character.
Delete text x X - Delete current ('x') or previous ('X') character dw - Delete the current word dd - Delete the current line D- Delete the rest of the line 5dd- Delete the next five lines 37Gdd- Delete line 37 J- Join lines Undo u - Undo most recent change to the file Brief Introduction to vi Editor
Global Searching and replace: /text - Search forward for some ?text- Search backward for some n- Repeat the previous search for the 'next' occurrence N- Repeat the previous search but in the opposite direction ' ' (two single quotes) - Go back to where you where previously :1,$s/oldtext/newtext/g - global substitutions Brief Introduction to vi Editor
Other popular commands ^ - go to start of line $ - go to end of line :1 - goes to top of file :5 - goes to fifth line of file :$ - goes to bottom of file :set nu - will number all your lines :set nonu - turn off line numbering Ctrl-g - show line number of current line Brief Introduction to vi Editor
To edit a file called filename, type nano filename. cntrl g - (^G) with display a Help file with a bunch of information about using nano. cntrl o - (^O) or (f3) will write or save the file cntrl x - (^X) will exit the program and return you to the prompt cntrl d - (^D) delete character currently under the cursor cntrl k - (^K) delete entire line cntrl u - (^U) paste text ^\ - search for (and replace) a string of characters BackSpace delete character currently in front of the cursor Brief Introduction to Nano Editor
C++ file g++ [options] source_file –o outputfile g++ myfile.cpp g++ -Wall myfile.cpp -o outputfile C file gcc [options] source_file –o outputfile gcc myfile.c java file javac Myfile.java java Myfile Compiling files in linux
gdb outputfile To set the break (gdb) break filename:line number (gdb) functionname To remove the break (gdb) clear function /line number To run (gdb) r (gdb) step (each step) (gdb) next [count] // how many line Debuggin c/c++ file
To watch the variables (gdb) watch variablename (gdb) watch expression To quit (gdb) q Debuggin c/c++ file