# first time
the 8887 th line of test.txt is 8888
the 18887 th line of test.txt is 18888
the 28888 th line of test.txt is 28888

#second time
the 8888 th line of test.txt is 8888
the 18888 th line of test.txt is 18888
the 28889 th line of test.txt is 28888

#third time
the 8887 th line of test.txt is 8888
the 28887 th line of test.txt is 28888
Use of uninitialized value in pattern match (m//) at serarch_file.pl line 42, <$
fh> line 29884.
Use of uninitialized value in pattern match (m//) at serarch_file.pl line 42, <$
fh> line 29884.
Use of uninitialized value in pattern match (m//) at serarch_file.pl line 42, <$
fh> line 29884.
Use of uninitialized value in pattern match (m//) at serarch_file.pl line 42, <$
fh> line 29884.
Use of uninitialized value in pattern match (m//) at serarch_file.pl line 42, <$
fh> line 29884.