fastq file with "." in sequence line

[zinky]

hi everyone ,
my fastq file contains sequence with "." in it like:
@

TTTAA.GAATAATAAGTCTAATCCCCTTCTATTCTGTAGCACCACTTCGGACAGGGAAGTTAAAGATTCTTCTAATTTGGTTATAGACTGTTCTATAGTT
+
Z\_`a@QQ[Y[Qb^bfa_ghd_[deZbaebecffhhfeddeeddebeec_Z__abbbec\_d]\_c_R`bdd]]c^H^]cZ_`bcaaaa``a_`ZZTTZ_
@
CGAGTGCTGCCGGTCTCCTACGGGAGCAAGTGGCGCAGCTCAAGCAGAAGGTCATGACCCATGTCCGCCACGGCTGCCAGCTGCTGCCAGGGCCTAACGA
+
___cccecgege^[bdgf`aefadU^cebgXcdf^eag`cgfdbR\cgR\\V\HV^b_b`aZ]GGGKKGKKWWTEOQWSGGGJRGJYGGGGEGJGGGGGG
@
C.GGAGTGCAGCTCTCACAGCTGGCTGCAACCGGCACTTATCTTAAAGTGAAAGCAGTTTTTCTGTTAACAAGAGACGGGATGGGGGGGACAGGGGGATG
+
\@P``cc^aecaeghb_f]ghefhcaP^ddgfghhhdc[cbgfagXbe[bfgd]_c`_V\d`dddggddcb]_bQ]Z^Y_QFTTXGOOOEHJW^[aEEEG
@1
AACACTCCTAAGGATCAGGGCCCCTGTTATGATTCCTCGGTCTCCAGTGGCGTCCAGGGTGCCACACCGGGGGGGCGATGCAACCCCCTGGCCTTAGAAT
+
_bbeceeefgggghhiichfhiihiihhhhiiiihiiiihZe`ghdgff_gfafghfhe\bZaadeV`[_]accEOXTTX[GY_`]_aXW^P[R]_bY`b
@
C.CTCCTATACTTTAAAGGATTATGTATTTAAGGAGCTCCAGCGAGACTGG.CAGGTTACAGTGAGACAGACAGACAGACATTGGATTTGGTGCTCTCTA
+
b@P\acc`gggggfaaaghffefhh^cghfffhghhhhfhhffffh[ehhf@LL[__\e_f_\dbg`dbbdaecbXZ]`Z\_RZGZGZbb_[^b]T]Y`G
@
ATAGATGTCTGGACTCTCTTAAATGGAAACAAAGATGACTTCCTCATCTATGACAGATGTGGCCGTCTTGGGTATCACCTTGGGTTGCCTTACTCCTTCC
+
_ZZa^ccc^^e]b`acafad[bcga[^edgf`fg`XYbfg_a^ef]eg]cgdS^a^cghc`gfbaff_Z\HGLH\VV`_ZZ^]GTZW\]]]Z`RTYY_T]

for some reason , machine numbers were masked
at beginning of red sequences above ,there are "." in it . and i hava no idea what it is . so anyone can explain it and give an advice on how to deal with reads like that. thanks a lot

[zinky]

o i know "." means N .......

[sklages]

... what usually happens with home-made converters qseq-to-fastq ...

[swbarnes2]

use sed to change all the '.' to 'N'