; && -- questions... whats the diffrence??

trey85stang · 05-12-2004, 09:31 AM

can anyone explain the following to me....

When i compile something that takes multiple commands i do the following...

Code:

sh configure ; make ; make install

What is the diffrence between the above and the following

Code:

sh configure && make && make install &&

And while I am at it... what is /dev/null & what is it used for??

thanks
trey

ranger_nemo · 05-12-2004, 10:08 AM

When using the semi-colons, all the commands will be run... If the make fails, the make install will still be run.

When using the double-ampersands, the following command will only be run if the preceeding command exitted without any errors... If the make fails, the make install won't be run.

/dev/null is a virtual device... Anything sent to it just disappears. It's used a lot when not wanting to see output from a program... my_script.sh > /dev/null

trey85stang · 05-12-2004, 01:32 PM

Quote:

Originally posted by ranger_nemo
When using the semi-colons, all the commands will be run... If the make fails, the make install will still be run.

When using the double-ampersands, the following command will only be run if the preceeding command exitted without any errors... If the make fails, the make install won't be run.

/dev/null is a virtual device... Anything sent to it just disappears. It's used a lot when not wanting to see output from a program... my_script.sh > /dev/null

Awesome!! thank you for the info!