unix Basic console commands file manipulation commands

Example

List of commands that will be introduced here:

ls     #view contents of a directory
touch  #create new file
mkdir  #create new directory
cp     #copy contents of one file to another
mv     #move file from one location to another
rm     #delete a file or directory

ls examples

jennifer@my_computer:~/Desktop$ ls
c++ projects    Research Paper.docx     test.cpp

shows the current directory

jennifer@my_computer:~/Desktop$ ls c++\ projects
DNA_analysis.cpp        encryption.cpp  pool_game.cpp

shows the directory "c++ projects". Space characters in file names are typed as "\ ".

touch example

jennifer@my_computer:~/Desktop$ ls
c++ projects    Research Paper.docx     test.cpp
jennifer@my_computer:~/Desktop$ touch ruby_test.rb
jennifer@my_computer:~/Desktop$ ls
c++ projects    Research Paper.docx     ruby_test.rb    test.cpp

mkdir example

jennifer@my_computer:~/Desktop$ mkdir ruby
jennifer@my_computer:~/Desktop$ ls
c++ projects    Research Paper.docx     ruby    ruby_test.rb    test.cpp
jennifer@my_computer:~/Desktop$ cd ruby
jennifer@my_computer:~/Desktop/ruby$ ls
<nothing>
jennifer@my_computer:~/Desktop/ruby

It doesn't actually print <nothing>. It's just how I'm representing that it doesn't output anything

cp examples

jennifer@my_computer:~/Desktop/ruby$ cd ..
jennifer@my_computer:~/Desktop$ cp test.cpp c++_test.cpp
jennifer@my_computer:~/Desktop$ ls
c++ projects    c++_test.cpp    Research Paper.docx     ruby    ruby_test.rb
test.cpp

This is when the last arg to cp, in this case "c++_test.cpp" is not an existing directory. cp will create a file called "c++_test.cpp", with contents identical to that of "test.cpp". If c++_test.cpp already existed, cp would have deleted what was previously there before copying the contents of "test.cpp" over.

jennifer@my_comptuer:~/Desktop$ ls ruby
<nothing>
jennifer@my_computer:~/Desktop$ cp ruby_test.rb ruby
jennifer@my_computer:~/Desktop$ ls ruby
ruby_test.rb

This is what happens when the last arg to cp, in this case "ruby", is a directory. cp creates a file with the same name as "ruby_test.rb", but in the directory "ruby".

mv examples

jennifer@my_computer:~/Desktop$ ls
c++ projects    c++_test.cpp    Research Paper.docx     ruby    ruby_test.rb
test.cpp
jennifer@my_computer:~/Desktop$ mv ruby_test.rb ruby\ test.rb
jennifer@my_computer:~/Desktop$ ls
c++ projects    c++_test.cpp    Research Paper.docx     ruby    ruby test.rb
test.cpp

This is what happens when the last arg to mv, in this case "ruby test.rb", is not an existing directory. The file "ruby_test.rb" has been renamed to "ruby test.rb". If "ruby test.rb" already existed, it would have been overwritten Note, again, that spaces are preceded by a ''.

jennifer@my_computer:~/Desktop$ ls
c++ projects    c++_test.cpp    Research Paper.docx     ruby    ruby test.rb
test.cpp
jennifer@my_computer:~/Desktop$ ls c++\ projects
DNA_analysis.cpp        encryption.cpp  pool_game.cpp
jennifer@my_computer:~/Desktop$ mv test.cpp c++\ projects
jennifer@my_computer:~/Desktop$ ls
c++ projects    c++_test.cpp    Research Paper.docx     ruby    ruby test.rb
jennifer@my_computer:~/Desktop$ ls c++\ projects
DNA_analysis.cpp        encryption.cpp  pool_game.cpp   test.cpp

This is what happens when mv is a directory that already existed. The file "test.cpp" gets moved to the directory "c++ projects".

rm examples

jennifer@my_computer:~/Desktop$ ls
c++ projects    c++_test.cpp    Research Paper.docx     ruby    ruby test.rb
jennifer@my_computer:~/Desktop$ rm c++_test.cpp
jennifer@my_computer:~/Desktop$ ls
c++ projects    Research Paper.docx     ruby    ruby test.rb

c++_test.cpp has been deleted

jennifer@my_computer:~/Desktop$ rm c++\ projects
rm: cannot remove 'c++ projects': Is a directory
jennifer@my_computer:~/Desktop$ ls
c++ projects    Research Paper.docx     ruby    ruby test.rb

rm has an extra requirement to delete directories

jennifer@my_computer:~/Desktop$ rm -rf c++\ projects
jennifer@my_computer:~/Desktop$ ls
Research Paper.docx     ruby    ruby test.rb

-rf must be added to delete a directory.

To learn more about ls, type the command ls --help. For touch, type touch --help. Likewise with all 6 commands mentioned here. This prints out a detailed explanation of use without creating or deleting anything.