how to check a file to contain only ascii charaters

UNIX for Beginners Q & A UNIX for Dummies Questions & Answers
1

HI
I need to validate a file in UNIX to contain only ascii characters.This is a production issue.Can anyone help with the command?
Thanks
Subbarao

2

ASCII compared to what EBCDIC?

7 bit ASCII characters are all less than 128 in decimal values (i.e. 0 - 127).