SYSTEM COMMANDS

 

uname -a

Display linux system information 

 

 

uname -r

Display kernel release information

 

 

last reboot

Show system reboot history

 

 

date

Show current date and time

 

 

cal

Show current month calendar4

 

 

whoami

Who you are logged in as 

 

 

finger user

Display information about user

 

 

cat /proc/cpuinfo

Show cpu info

 

 

cat /proc/meminfo 

Show memory information


 

man command

Show manual for command

 

 

df

Check filesytem storage


 

du

Check subdirectories


 

df -h            

Shows file size which is user readable

 

 

du --max-depth=1 -h  

Check subdirectories by one level down


 

whereis app

Show possible location of app

 

 

which app

Show which app will be run by default
 

 

free      

To check ram & swap partition  usuage

 

 

free -g

To see usuage in gigabytes

 

 

dd if=/dev/zero of=/swapfile bs=1024 count=1024

 

dd to create a storage file

if=/dev/zero : Read from /dev/zero file.  /dev/zero is a special file in that provides as many null characters to build storage file called /swapfile.
of=/swapfile : Read from /dev/zero write storage file to /swapfile.
bs=1024 : Read and write 1024 BYTES bytes at a time.
count=1024 : Copy only 1024 BLOCKS input blocks.

 

 

mkswap /swapfile 

To setup a linux swap area in a file.

 

 

swapon /swapfile
Enable the swap file.

 

 

swapoff /swapfile

 

Disable the swap file.

Determine the size of the new swap file in megabytes and multiply by 1024 to determine the number of blocks. For example, the block size of a 64 MB swap file is 65536. 

 

 

lvextend -l +100  /logical/volume00

Extend the logical volume 00 from blank space i.e. 0mb to volume 00 with 100 mb...

 

 

ctrl+alt+f1    

GUI (Graphical mode) to text mode i.e. CLI(Command Line Interface)

 

 

ctrl+alt+f7    

Text to graphic mode

 

Types Of Boot Loader
grub  grand unified boot loader
lilo linux bootloader

 

kcontrol &      

Configure the kde enviroment

 

 

gnome-control-center      

Configure the gnome enviroment

 

switchdesk kde  

Set the default startup to kde

 

 

switchdesk gnome  

Set the default startup to gnome

 

 

up2date-config      

Configure the red hat for update

 

 

mount /dev/sda1  /tmpdir         mount the sda1 file in tmpdir directory


mount /dev/sda0 /tmpdir          mount the sda0 file in tmpdir directory


unmount  /tmpdir/boot   unmount boot directory


unmount /tmpdir                 unmunt tmpdir directory
 

 

sync

Sync the changed or changes take effect


 

top    

Will show the running process list
 

 

gnome-system-monitor  

Show the graphical mode of running process

 

uptime    

 

  • Show how long the system is running from last boot 
  • load average of first no show the the total load in last one minute 
  • load average of second no show the the total load in last five minute
  • load average of third no show the the total load in last fifteen minute
     
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