regex, string match question

[patricklcam]

Hi,

I am learning regex and was wonder about parsing a time string using egrep.

File test.txt contains:
09:23 PM
99:23 PM
9:23 PM
11:23 AM

Command line:
$> egrep -i '(1[012]|0[1-9]|(\<[1-9])):[0-5][0-9] (am|pm)' test.txt

1[012] gets 10 11 12
0[1-9] matches 01-09
\<[1-9] matches 1-9: // Eliminates the 99:23, not sure about this as a good solution

Is there a better way to restrict the initial match to 1-9: or 01-09: or 10-12: ?

Thanks in advance

Pat

[ghostdog74]

why make it so complicated. Use awk and set field delimiter to either space and semi colon

# awk 'BEGIN{FS=":|[ ]"} $1 <= 12 && $2 <=59 && $3 ~/AM|PM/' file
09:23 PM
9:23 PM
11:23 AM