On Thu, Dec 17, 2009 at 08:45:02PM -0500, Greg Larkin wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Warren Block wrote: > > On Fri, 18 Dec 2009, Anton Shterenlikht wrote: > > > >> I'm creating binary files in fortran. > >> Fortran adds 4 byte record delimiters at the beginning > >> and the end of each record, which, in the case of a binary > >> file, is just at the beginning and at the end of the file. > >> I need to delete these record delimiters, because the > >> software I use to visualise the binary files interprets > >> them as data. But I don't know how. I've looked at > >> hexdump and od, but those are only dumping (I think) > >> file contents, and I cannot see how to edit a file with them. > > > > truncate -4 myfile should get rid of the last four bytes. Maybe there's > > a similar efficient way to truncate the start of a file. > > > > -Warren Block * Rapid City, South Dakota USA > > This should do it: > > dd if=oldfile of=newfile bs=1 skip=4
yes, this is very useful: > hexdump -C fort.10 00000000 01 00 00 00 08 01 00 00 00 |.........| 00000009 > truncate -s -4 fort.10 > hexdump -C fort.10 00000000 01 00 00 00 08 |.....| 00000005 > dd if=fort.10 of=zzz bs=1 skip=4 1+0 records in 1+0 records out 1 bytes transferred in 0.000094 secs (10645 bytes/sec) > hexdump -C zzz 00000000 08 |.| 00000001 > many thanks anton -- Anton Shterenlikht Room 2.6, Queen's Building Mech Eng Dept Bristol University University Walk, Bristol BS8 1TR, UK Tel: +44 (0)117 331 5944 Fax: +44 (0)117 929 4423 _______________________________________________ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"