tar .vs. cpio - (nf)

[William L. Sebok]

>In article <226 at haddock.UUCP> johnl at haddock.UUCP writes:
>>  - reading file names from stdin is a feature, not a bug.  You can use
>>    find to enumerate just the files you want rather than having to dump
>>    everything in a directory tree, e.g.
>>
>>	$ find somedir -mtime -14 -print | cpio -oB >/dev/rmt0
>>
>>    (dump only files modified within the last two weeks.)  Doing this
>>    with tar is pretty hard.
>
>It isn't really very hard:
>	tar <options> `find ...`
>
>Accepting file names on the command line is the Unix convention.
>    Barry Margolin

No.  It may be the Unix convention but it is not useful for dumping large
numbers of files (like when doing a backup).  There is a limit on how large
an argument list can be passed to a program.  On the Vax under 4.2 BSD as
distributed this is 10240 characters.  This can be easily exceeded in a
medium large file system.  Heck, it is sometimes exceeded in a run-away
uucp spool directory.
-- 
Bill Sebok			Princeton University, Astrophysics
{allegra,akgua,burl,cbosgd,decvax,ihnp4,noao,princeton,vax135}!astrovax!wls