Shell Programming and Scripting

Originally Posted by summer_cherry

nawk 'BEGIN{FS="\n";RS=""}
{
if(index($3,"Regards")!=0)
print $0
}' filename

VARIABLES, RECORDS AND FIELDS
AWK variables are dynamic; they come into existence when they are first used.
Their values are either floating-point numbers or strings, or both, depending upon
how they are used. AWK also has one dimensional arrays; arrays with multiple
dimensions may be simulated. Several pre-defined variables are set as a program
runs; these are described as needed and summarized below.
Records
Normally, records are separated by newline characters. You can control how records
are separated by assigning values to the built-in variable RS. If RS is any single
character, that character separates records. Otherwise, RS is a regular expres-
sion. Text in the input that matches this regular expression separates the record.
However, in compatibility mode, only the first character of its string value is
used for separating records. If RS is set to the null string, then records are
separated by blank lines. When RS is set to the null string, the newline character
always acts as a field separator, in addition to whatever value FS may have.
Fields
As each input record is read, gawk splits the record into fields, using the value
of the FS variable as the field separator. If FS is a single character, fields are
separated by that character. If FS is the null string, then each individual char-
acter becomes a separate field. Otherwise, FS is expected to be a full regular
expression. In the special case that FS is a single space, fields are separated by
runs of spaces and/or tabs and/or newlines. (But see the section POSIX COMPATIBIL-
ITY, below). NOTE: The value of IGNORECASE (see below) also affects how fields are
split when FS is a regular expression, and how records are separated when RS is a
regular expression.

. . . . .

Built-in Variables
FS The input field separator, a space by default.
RS The input record separator, by default a newline.