Starting & Stopping
shutdown -h now – Shutdown the system now and do not reboot.
halt – Stop all processes – same as above.
shutdown -r 5 – Shutdown the system in 5 minutes and reboot.
shutdown -r now – Shutdown the system now and reboot.
reboot – Stop all processes and then reboot – as above.
startx – Start the X system.
Accessing & mounting file systems
mount -t iso9660 /dev/cdrom /mnt/cdrom – Mount the device cdrom and call it cdrom under the /mnt directory.
mount -t msdos /dev/hdd /mnt/ddrive – Mount hard disk “d” as a msdos file system and call it ddrive under the /mnt directory.
mount -t vfat /dev/hda1 /mnt/cdrive – Mount hard disk “a” as a VFAT file system and call it cdrive under the /mnt directory.
umount /mnt/cdrom – Unmount the cdrom
Finding files and text within files
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
locate missingfilename – Find a file called missingfilename using the locate command – this assumes you have already used the command updatedb (see next).
updatedb – Create or update the database of files on all file systems attached to the linux root directory.
which missingfilename – Show the subdirectory containing the executable file called missingfilename.
grep textstringtofind – Starting with the directory called dir, /dir look for and list all files containing textstringtofind.
Moving, copying, deleting & viewing files
ls -l – List files in current directory using long format.
ls -F – List files in current directory and indicate the file type.
ls -laC – List all files in current directory in long format and display in columns.
rm name – Remove a file or directory called name.
rm -rf name – Kill off an entire directory and all that includes files and subdirectories.
cp filename /home/dirname – Copy the file called filename to the /home/dirname directory.
mv filename /home/dirname – Move the file called filename to the /home/dirname directory.
cat filetoview – Display the file called filetoview.
man -k keyword – Display man pages containing keyword.
more filetoview – Display the file called filetoview one page at a time, proceed to next page using the spacebar.
head filetoview – Display the first 10 lines of the file called filetoview.
head -20 filetoview – Display the first 20 lines of the file called filetoview.
tail filetoview – Display the last 10 lines of the file called filetoview.
tail -20 filetoview – Display the last 20 lines of the file called filetoview.
Installing software for Linux
rpm -ihv name.rpm – Install the rpm package called name.
rpm -Uhv name.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.
rpm -ql package – List the files and state the installed version of the package called package.
rpm -i –force package – Reinstall the rpm package called package having deleted parts of it (not deleting using rpm -e).
tar -zxvf archive.tar.gz or tar -zxvf archive.tgz – Decompress the files contained in the zipped and tarred archive called archive
./configure – Execute the script preparing the installed files for compiling.
adduser accountname – Create a new user call accountname.
passwd accountname – Give accountname a new password.
su – Log in as superuser from current login.
exit – Stop being superuser and revert to normal user.
Source :: Softpedia