1. Basic UNIX commands
> ls
List the contents in current directory.
> ls -alF
List the contents in long format in the current directory.
> cd directoryname
Change current directory to another directory.
> mkdir directoryname
Create a directory.
> cp file1.txt file2.txt
Make a copy of file1.txt.
> mv /home/harpreet/file1.txt /tmp/file2.txt
Move the file to different location or can be used for renaming a file.
> rm filename.txt
Delete a file.
> rm -R directoryname
Delete the contents of a directory.
> head -20 filename.txt
Get 20 lines from the top of the file.
> tail -30 filename.txt
Get 30 lines from the bottom of the file.
2. vi filename.txt
Edit a file.
a. Esc dd
Deletes the current line
b. Esc u
Undo the last action
c. Esc :0 (zero)
Move cursor to first line of file
d. Esc $
Move to end of current line
e. Esc Shift+g
Move to end of file
f. Esc yy
Copy the current line
Esc y3y
Copy the next three lines
g. Esc p
Paste the copied line(s)
h. Esc :35
Moves the cursor to line number 35
i. Esc /wordtofind
Find the word within the file. Press 'n' to move to the next occurrence.
3. > grep 'wordtofind' filename.txt
Finds the line containing a string from the file
grep -i 'wordtofind' filename.txt
Case-insensitive find.
4. > find /tmp/directoryname -name test.txt
Find a file with name 'test.txt' in the given path.
5. > find . -type f -exec grep -i Row2 {} \; -print
Find the word 'row2' from all the files in current path.
Also, shows the line containing an occurrence of the word.
6. > scp harpreet@hostname.edu:/tmp/file.txt .
Copy a file located on another server to the current directory on the present server.
> scp file.txt harpreet@hostname.edu:.
Copy a file from current server to another server into your home directory.
> scp file.txt harpreet@hostname.edu:/home/directory/file.txt
Copy a file from one machine to another.
7. > tar cvzf new_tar_file.tar.gz file1.txt file2.txt
Create a tar file new_tar_file.tar.gz containing file1.txt and file2.txt
> tar xvzf abc.tar.gz
Untar the contents of a file abc.tar.gz to the current directory
8. awk - Let us create a file 'test.txt' with these contents
Row1-column1 Row1-column2 Row1-column3 Row1-column4
Row2-column1 Row2-column2-HARPREET Row2-column3 Row2-column4
Row3-column1 Row3-column2 Row3-column3 Row3-column4-SINGH
Observe the output for various commands
> awk '{print $2}' test.txt
Row1-column2
Row2-column2-HARPREET
Row3-column2
The above command prints the second column
String matching using awk :
> awk '{if ( $4 ~ /SINGH/ ) { print $2 $3}}' test.txt
Row3-column2Row3-column3
The above command matches the string 'SINGH' and prints column 2 and 3.
Corrections/improvements/questions are welcome :)
