[bug-obsolete-packages] xargs tar: silent limit on length of argument list

[Ed Avis]

I understand that my operating system (Linux 2.6.35) has various limits on the
maximum size of argument lists.  I expected that if I bumped up against them,
then xargs would fail with an error message.  But when using xargs together with
GNU tar to read a list of filenames, the list gets truncated after 131072 bytes
without any message.  I am doing

% xargs tar c <~/filelist | tar t | diff -u ~/filelist -

No messages are produced on stderr, but diff's output shows that not all files
in the list are making it into the destination archive.  The list seems to be
truncated at the point where adding one more line would cross the 131072 byte
limit.

Or is it GNU tar that has the silent truncation behaviour?

% xargs --version | head -n 1
xargs (GNU findutils) 4.5.9
% tar --version | head -n 1
tar (GNU tar) 1.23
% xargs --show-limits
Your environment variables take up 1665 bytes
POSIX upper limit on argument length (this system): 2176287
POSIX smallest allowable upper limit on argument length (all systems): 4096
Maximum length of command we could actually use: 2174622
Size of command buffer we are actually using: 131072

-- 
Ed Avis <address@hidden>