UNIX for Beginners Questions & Answers

Forget putting your code in a script!

What happens when you run the following commands directly in your shell:

Code:

gedit somefile& PID=$!
wait $PID

where somefile is the name of some file that you can edit? If this didn't work for you when run outside of a script, what makes you think it should work when you run it inside a script?

As I said in post #12 in this thread:
Jobs run in the background are blocked if they try to read from or write to their controlling terminal. The wait command that you are executing is not reporting that gedit terminated; it is reporting that gedit was stopped (probably by a SIGTTOU or SIGTTIN signal).

Maybe issuing the following command line in a shell would be instructive:

Code:

gedit somefile& PID=$!; sleep 10; jobs $PID; sleep 10; fg $PID

I can't speak for gedit, but leafpad, be it sent to background or not, opens a new window with an editing session.

Sorry, I didn't really understand what you meant. When running those commands in the terminal this was the result:

Code:

adam@adam-VirtualBox:~/Systems$ gedit ex_03.sh & PID=$!
[1] 23022
adam@adam-VirtualBox:~/Systems$ wait $PID
[1]+  Done                    gedit ex_03.sh

So it works properly there? I'm totally new to this though so I don't understand why something like that wouldn't work in a .sh script?

---------- Post updated at 01:20 PM ---------- Previous update was at 01:17 PM ----------

I'm sorry the reason I've not done this is I don't know how? Any further help would be greatly appreciated.

The code I suggested?

Code:

gedit filename
echo "Editor has now quit"

Code:

adam@adam-VirtualBox:~/Systems$ gedit Repository.sh 
adam@adam-VirtualBox:~/Systems$ echo "File closed."
File closed.

I didn't need to close the file or anything - whereas when I use a different system I normally have to CTRL+C or something to use the terminal once I've used it to open a file. Just noticed this now.

No one's mentioned lock files and race conditions yet. Go us!

OK. I don't have leafpad or gedit on my system. When testing with vi (note that in post #10, the O.P. said that gedit and vi were used interchangeably), by running the command line:

Code:

vi somefile& PID=$!; sleep 10; jobs $PID; sleep 10; fg $PID

I immediately get:

Code:

vi somefile& PID=$!; sleep 10; jobs $PID; sleep 10; fg $PID
[1]	83379

and about 10 seconds later I get:

Code:

[1] + Stopped (SIGTTOU)        vi somefile& PID=$!; sleep 10; jobs $PID; sleep 10; fg $PID

noting that vi is stopped; not terminated. And about 10 seconds later, the fg $PID brings vi somefile into the foreground so I can edit somefile. When I quit vi, I then get a new shell prompt for another command.