What is the difference between running a process using nohup and running a process in background ? Please explain

Hi,

nohup - no hangup

when you suffix with & for running some task, this task will run in background.
example

cat ex.txt|sort &

if you want to continue this job after you log out from your terminal, you can prefix with nohup

nohup cat ex.txt|nohup sort &

Thanks,
Shahnaz.

what is the difference between nohup and & say

1)nohup cat test.dat

and

2)cat test.dat &

and

3) nohup cat test.dat &

By nohup you say no hangup, what do you mean by no hangup? Please explain more

Thanks

From the documentation of nohup:

When you run a command from an interactive shell you have a "controlling terminal" managed by sshd, telnetd, xterm or whatever.

Then that controlling terminal closes it sends the processes under it's umbrella a 'SIGHUP' signal, this will normally kill those processes. 'nohup' traps this signal and may detach from the controlling terminal.