matching 3 digits at the begining and the end of the line

I have a file with hundreds of records and I need to find those records that have three digits at the beginning and the same three digits at the end.

$GREP '\([a-z]\)\([a-z]\)\([a-z]\)\3\2\1'I

believe this is part of the script but I am not sure how to compare these 3 digits with the 3 digits at the end of the same line. Any help is appreciated. Thank you.

Here is an awk example

awk 'substr($0,1,3)==substr($4,length($0)-3)'  inputfilename

this awk syntax uses the implied print $0, when the boolean statement evauates to true.

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