Basic Linux Commands for Beginners

Using a Linux machine using a shell Prompt is always a challenge these days. Many of us feel it is tougher to use Linux because of its Conventional Shell prompt, but the GUIs are so sophisticated when compared with Other Operating systems like windows, etc.

But still as a developer, one has to be good at Linux both in the GUI and as well as in Shell. For novice users and beginners, the following commands will make understand the importance of Linux and their commands.

Basic Commands

Commands usage Explanation
ls ls to list the files and folders
ls –l ls –l to list the files and folders in long format
chmod chmod 777 filename to change the mode of a file
pwd pwd display the present working directory
passwd passwd Changing the password of the current user
echo echo “hello” display the string hello
  echo $PATH Display the PATH Variable stored
  echo $HOME display the Home folder of the current user
  echo $SHELL displays the type of shell used /bin/bash
tar tar xf filename.tar to decompress the tar file and extract the folders
  tar xvf filename.tar to decompress the tar file and extract the folders with verbose mode
  tar zxvf filename.tar.gz to decompress from gzip and the extract the tar created.
gzip gzip –d filename.tar.gz
gzip –d filename.gz
to decompress the gzip file
bzip2 bzip2 –d filename.tar.bz2
bzip2 –d filename.bz2
to decompress the bzip2 file
rm rm name remove a file or directory called name (the directory should be empty to be deleted)
  rm –rf name

Kill off an entire directory and all it’s
includes files and subdirectories

cp cp filename /home/hello copy the file called filename to the folder /home/hello
mv mv filename /home/hello move the file called filename to the directory /home/hello
cat cat filename display the file called filename
su su login to superuser from current login (you should know the super user password)
exit exit exit out of the shell window or Stop being superuser and revert to normal user
dmesg dmesg display the boot time messages
ls ls list current processes
kill kill 123 kill a specific process with ID 123
ifconfig ifconfig

List ip addresses for all devices on
the machine

rpm rpm –ivh filename.rpm Install the rpm package called name
  rpm –Uvh filename.rpm

Upgrade the rpm package called
name

  rpm –e package

Delete the rpm package called
package

  rpm –l package

List the files in the package called
package

./configure ./configure

Execute the script preparing the
installed files for compiling

find find / –name fname

Starting with the root directory, look
for the file called fname

  find / -name ”*fname*”

Starting with the root directory, look
for the file containing the string fname

 

File Permissions

image

If the command ls -l is given, a long list of file names is displayed. The first column in this list details the permissions  applying to the file. If a permission is missing for a owner,
group of other, it is represented by - eg.

drwxr-x--x
Read = 4
Write = 2
Execute = 1
File permissions are altered by giving the chmod command and the appropriate octal code for each user type. eg chmod 7 6 4 filename will make the file called filename R+W+X for the owner, R+W for the group and R for others.

chmod 7 5 5 Full permission for the owner, read and execute access for the group and others.
chmod +x filename Make the file called filename executable to all users.

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