UNIX for Dummies Questions & Answers

When using the -k switch for the sort command I think it will sort the lines in the file based on the field number specified after -k, for example
$ sort -k 3 testfile
would sort the lines in testfile based on the 3rd field of each line, with separate fields only being recognized if they are separated by a space or tab. Do I have this correct?
Is the -t switch used to designate a character other than a space or tab as a field separator?

You are correct - the -t will change the character (you might need to put it in quotes), and remember, if you change the character, sort will then change how it looks at the file - your fields will now be split by that character.

Normal:
Mar 10 08:01:34 server ntpdate[172]: waiting 300 seconds before trying again

First field is Mar.

If you use -t"[", first field is "Mar 10 08:01:34 server ntpdate"

Thanks, I read the man page, but as often happens I found it hard to interpret exactly how to use the information it contained to create working commands. Your example of use of the -t switch is exactly what I needed. I find descriptions in man pages generally too vague for this newbie.