delete a line in a file with a shell script??

[pedrosacosta]

What shell script should i use to delete a line of text from a text file? The line is selected by a pattern defined by the user.

I'll give this example:
File.txt

qwerty;;12345
asdfgh;;4567
zxcvbn;;7890

If i want to delete the second line i will give the following pattern:

*456*, and then, the command will delete the whole second line.

How can i do this with shell script?

Thanks,
Pedro

[jop_bal]

mmm....
I amn't sure if there is a simpler method. anyway sed comes in handy.

sed '/<your expression>/d' (source file name) > tempfile
cat tempfile > (source file name)
rm tempfile

File.txt
qwerty;;12345
asdfgh;;4567
zxcvbn;;7890

in our example:
sed '/456/d' file.txt > tmpf
cat tmpf > file.txt
rm tmpf

But this is a bit costly logic. Anyone to help out further?