pack.1 (2010 09)

pack(1) pack(1)

pcat returns the number of ﬁles it was unable to unpack. Failure may occur if:

• The ﬁle name (exclusive of the

.z) has more than 12 characters;

• The ﬁle cannot be opened;

• The ﬁle does not appear to have been created by pack .

unpack expands ﬁles created by pack. For each ﬁle name speciﬁed in the command, a search is made

for a ﬁle called name

(or just name if name ends in .z). If this ﬁle appears to be a packed ﬁle, it is

replaced by its expanded version. The new ﬁle has the

.z sufﬁx stripped from its name, and has the

same access modes, access and modiﬁcation dates, and owner as those of the packed ﬁle.

unpack returns a value that is the number of ﬁles it was unable to unpack. Failure may occur for the

reasons given for pcat, as well as for the following:

• A ﬁle with the "unpacked" name already exists;

• The unpacked ﬁle cannot be created.

Access Control Lists (ACLs)

pack retains all entries in a ﬁle’s access control list when compressing and expanding it (see acl (5)).

DEPENDENCIES

NFS

Optional access control list entries of networked ﬁles are summarized (as returned in

st_mode by

stat(), but not copied to the new ﬁle (see stat (2)).

WARNINGS

This command is likely to be withdrawn from X/Open standards. Applications using this command might

not be portable to other vendors’ systems. Instead of

pack

it is recommended that you use the

compress utility as it has the following advantages:

• The algorithm used to create the output ﬁles is frequently more effective in reducing the size of ﬁles

• The compress utility can compress data from its standard input, not just a named regular ﬁle. Thus

it is useful in pipelines

zcat is recommended instead of pcat and, uncompress is recommended instead of unpack.