Mauricio Silveira wrote: > I'm wondering if there's any way to get tar to stop immediately after > the extraction of a file on compressed tar files. eg: I pack a big tgz > with the file index.txt first so that when I run "tar xf file.tgz > --occurrence index.txt" it extracts "index.txt" but proceeds reading the > file. I wish tar stopped after extracting the intended file. > > I know it works for non-compressed tar archives.... --occurrence only works on files. When you extract a compressed archive, tar spawns a separate gzip process connected via a pipe. The effect is identical to: gzip -dc archive.tar.gz | tar xf - ... Terminating while reading from a pipe will cause the writing process to terminate abnormally (SIGPIPE, or if that is caught, EPIPE). This can have undesirable side effects, so tar always reads until EOF when reading from a pipe or socket. You could disable this behaviour by removing the call to sys_drain_input_pipe() from close_archive() in src/buffer.c. The sys_drain_input_pipe() function (in src/system.c) is preceded by the comment: /* Manage to fully drain a pipe we might be reading, so to not break it on the producer after the EOF block. FIXME: one of these days, GNU tar might become clever enough to just stop working, once there is no more work to do, we might have to revise this area in such time. */ If you regularly want to extract individual members from an archive, consider using an archive format which was designed for random access, e.g. zip. terry white wrote: > 'man tar' offers: > > -T, --files-from F > get names to extract or create from file F > > > : when I run "tar xf file.tgz --occurrence index.txt" > > HOWEVER , i'm using a gnu flavour 'tar', which does "not" list > '--occurrence' as an option, so, the suggestion above may not apply ... The --occurrence switch is relatively new; it's present in GNU tar 1.15.1. The -T switch has been around as long as I can remember, but it doesn't help here. -- Glynn Clements <glynn@xxxxxxxxxxxxxxxxxx> - To unsubscribe from this list: send the line "unsubscribe linux-admin" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
