CS 202 Computer Science II Lab

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CS 202Computer Science II Lab

• Fall 2009
• September 3

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Today Topics

• File Access Permissions
• Text Editors
• VI
• Emacs
• Compiling C Programs
• Accessing Linux Remotely
• Putty
• SSH

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File Access Permissions

• user u/group g/other o
• r or 4 read permission
• w or 2 write permission
• x or 1 execute permission
• - no permission
• chmod options file change file or directory
  access permissions (/-/)
• chmod 755 file1 or chmod urwx,gorx file1

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Text editors - emacs

• emacs/xemacs are text editors used to
  create/modify files
• emacs filename
• emacs cs202file.cpp
• Note
• C- Control (Ctrl) key
• M- Meta key, generally the Alt key but can also
  be the Esc key
• Essential Commands
• C-x,C-s Save the file
• C-x,C-w Save to a new file
• C-x,C-c Exit emacs
• C-x,u Undo last edit

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Text editors VI..

• There are two mode on this editor
• Command mode
• Text-entry mode
• vi filename
• Back to command mode by using Esc key

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.Text editors VI.

• Inserting text
• i insert before cursor
• a append after cursor
• R replace the text
• I, A, o, O
• Deleting text
• x delete character under cursor
• dw delete word under cursor
• dd delete line under cursor

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..Text editors VI

• Saving Files
• w ltfilenamegt save file as ltfilenamegt
• w save file with current name
• Exit program
• wq Save and Exit
• q! Exit without Save

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showInfo

• The content of showInfo.cpp
• include ltiostreamgt
• using namespace std
• int main()
• cout ltlt "My name is Ray" ltlt endl
• cout ltlt "My email is amayeh_at_cse.unr.edu" ltlt
  endl
• return 0

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Compiling and Running C programs on Linux

• The g compiler On Linux and many Unix systems
  the standard C compiler is called g.

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Compiling Program

• Primitive Compilation
• g ltprogramname.cppgt
• Compile with specified output name
• g -o ltouput filenamegt ltprogramname.cppgt
• Compile as object
• g -c -o ltobject filenamegt ltprogramname.cppgt
• Linking Program
• g -o ltobject filenamegt ltpg1.cppgt ltpg2.cppgt

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Hello World

• Using any text editor to create file called
  hello.cpp
• include ltiostreamgt
• using namespace std //use standard namespace
• int main()
• cout ltlt "Hello World" ltlt endl
• return 0
• g -o hello hello.cpp
• ./hello

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Remote Login

• Software
• SSH Secure Shell Client
• Putty
• WinSCP
• Host
• remote.ecc.unr.edu

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Remote Login -Putty
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Remote Login -Putty
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Remote Login -SSH
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Remote Login -SSH
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Remote Login -SSH
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Remote Login -SSH
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Remote Login -SSH
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• Questions?