Here is an explanation made using
RegexBuddy - also check
www.regular-expressions.info for tutorials, references and more.
^(.{62}(.{7}).{139}) {10}
Assert position at the beginning of a line (at beginning of the string or after a line break character) «^»
Match the regular expression below and capture its match into backreference number 1 «(.{62}(.{7}).{139})»
--Match any single character that is not a line break character «.{62}»
----Exactly 62 times «{62}»
--Match the regular expression below and capture its match into backreference number 2 «(.{7})»
----Match any single character that is not a line break character «.{7}»
------Exactly 7 times «{7}»
--Match any single character that is not a line break character «.{139}»
----Exactly 139 times «{139}»
Match the space character « {10}»
--Exactly 10 times «{10}»
So you see 62 and 139 are number of columns to skip past to get to the "interesting" columns.