Capturing Ctrl + C

[Radhe Webster]

I have created a script that is called out of a users .profile when they log in. In the script I have:

trap 'print "ENTER INFORMATION REQUESTED!"' INT
trap 'print "ENTER INFORMATION REQUESTED!"' QUIT

And then goes on to ask them for some requested information. For some reason it's not working correctly and ctrl + c breaks out of it. I've tried it with trap "" 1 2 3 and that isn't working either.

Any thoughts? Thanks

[Steve Steel]

Hi


Use stty to change the intr value at the start and end of script . see stty -a


Why the trap.How is the script used

see
www.shelldorado.com for good shell tips

Steve Steel

[Simon Hargrave · Accepted solution]

The way trap works is, it EITHER ignores the signal (if you use a null argument) OR it runs the command then processes the trap.

eg

trap '' INT

will make it ignore Ctrl-C

trap 'echo test' INT

will make it print the word "test", then exit the program.

You can't have both unfortunately.

[Radhe Webster]

It's so that our various vendors identify themselves (and we get emailed) when they log onto the system.

The command trap " INT generates syntax errors... should it not be trap "" INT

[Simon Hargrave]

I was using 2 single-quotes. I guess you read this as one double-quote? You can use either a pair of single-quotes or a pair of double-quotes, it doesn't make a difference when using a null string. When specifying a command your use depends on whether you want shell expansion.

[Radhe Webster]

I've gotten it to work by using stty to change the interrupt value, but trapping it is still not working.

[Stuart Browne]

What shell are you using?

And does it fail when you just use:

trap 'print blah' 2