Question

Can you help me?

I am taking an INTRODUCTORY unix/linux shell programming course and need to know what the following command will do. Need a SIMPLE answer please.

onsystem john1 &

Answer 1

onsystem john1 &

onsystem : there is no such command in linux.

I am treating this line as a dummy for elaborating concept behind it.

Here concept of job control is used. The & informs the shell to put the command in the background.

onsystem: can be any command here

john1: is parameter to that command

&: informs the shell to put the command in the background.

for example.

gedit temp.txt  this command tries to open a file named temp.txt if doesn't exists, it creates the file, but when you type this command you cannot use the same terminal for executing more commands.

gedit temp.txt &  now the ampersand puts the command execution in background. so you can use the same terminal for executing more commands.

Please write in comments if you want more information or still have some doubts.