$cat fic
Start
Serveur=anonyme
1212596 816 -rw-rw-r-- 1 toto groland 829924 nov. 29 04:35 /data/xpl/tmp/F0413691
1212871 35184 -rw-rw-r-- 1 toto groland 35984440 nov. 6 00:03 /data/xpl/tmp/F0397858.pi99
1212859 58048 -rw-rw-r-- 1 toto groland 59373540 nov. 3 14:22  /data/xpl/tmp/F0396850.pi99
1212891 684 -rw-rw-r-- 1 toto groland 693250 nov. 11 04:10 /data/xpl/tmp/F0401716
1212814 35200 -rw-rw-r-- 1 toto groland 36003240 oct. 30 00:01 /data/xpl/tmp/F0394328.pi99
213009 4 -rw-rw-r-- 1 toto groland 1044 oct. 12 17:23 /data/xpl/tmp/F0381021
1212720 4 -rw-rw-r-- 1 toto groland 40 oct. 14 17:29 /data/xpl/tmp/F0383063
1212721 4 -rw-rw-r-- 1 toto groland 2344 oct. 10 15:23 /data/xpl/tmp/F0378393
1212564 632 -rw-rw-r-- 1 toto groland 641737 nov. 28 04:41 /data/xpl/tmp/F0412689
End

$grep -Po '.*F\K[^.]*' fic
0397858
0396850
0394328