linux commands

1. who :
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This command will display…

a. All users logged in
b. tty device(line) they are using
c. When they logged in
d. Idle time
e. Where they logged in from
Options:

1. -i display idle time
2. -H print column headings

2. procinfo -fn30 —-> to view the below information.
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a. Last Boot time
b. Load Average
c. average number of jobs running
d. number of runnable processes
e. total number of processes
f. PID of the last process run (idem)
g. Swap info
h. Memory resources
i. Number of disks
j. IRQ info
k. Installed modules (with the -a or -m option)
l. File Systems (with the -a or -m option)

3. Hostname:
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a. hostname —-> With no options, displays the machine’s host name – linux
b. hostname -d —-> Display the domain name the machine belongs to – ourdomain.com
c. hostname -f —-> Display the fully qualified host and domain name – linux.ourdomain.com
d. hostname -i —-> Display the IP address for the current machine – 192.168.1.1

4. Nestat: netstat network connections, routing tables, interface statistics.
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The command netstat displays information for all active sockets, including the port numbers associated with each type of network service.

Options What it does

-o —-> Displays some additional information on networking timers
-a —-> Display all sockets, including the listening server sockets
-r —-> Displays kernel routing tables
-i —-> Display a table of all (or the specified iface) networking interfaces
-M —-> Display a list of all masqueraded sessions
-v —-> Tell the user what is going on by being verbose
-e —-> Additional information

#netstat -i —-> kernel inetrface table.

#netstat -r —-> kernel routing table.

5. Date:
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date – Displays current date/time: Sun Jun 11 12:56:54 CDT 2000

date MMDDhhmmCCYY.ss> – Sets the system date. (Note: must be logged in as root)
MM month
DD day within month
hh hour
mm minute
CC first two digits of year (optional)
YY last two digits of year (optional)
ss second (optional)