zoo
Hurricane Electric Internet Services
NAME
zoo - manipulate archives of files in compressed form
SYNOPSIS
zoo {acfDeghHlLPTuUvVx}[aAcCdEfghImMnNoOpPqSu1:/.@n+-=]
archive [file] ...
zoo -command archive [file] ...
zoo h
DESCRIPTION
Zoo is used to create and maintain collections of files in
compressed form. It uses a Lempel-Ziv compression algo-
rithm that gives space savings in the range of 20% to 80%
depending on the type of file data. Zoo can store and
selectively extract multiple generations of the same file.
Data can be recovered from damaged archives by skipping
the damaged portion and locating undamaged data with the
help of fiz(1).
This documentation is for version 2.1. Changes from pre-
vious versions are described in the section labelled
CHANGES.
The command zoo h gives a summary of commands. Extended
multiscreen help can be obtained with zoo H.
Zoo will not add an archive to itself, nor add the
archive's backup (with .bak extension to the filename) to
the archive.
Zoo has two types of commands: Expert commands, which
consist of one command letter followed by zero or more
modifier characters, and Novice commands, which consist of
a hyphen (`-') followed by a command word that may be
abbreviated. Expert commands are case-sensitive but
Novice commands are not.
When zoo adds a file to an existing archive, the default
action is to maintain one generation of each file in an
archive and to mark any older generation as deleted. A
limit on the number of generations to save can be speci-
fied by the user for an entire archive, or for each file
individually, or both. Zoo deletes a stored copy of an
added file if necessary to prevent the number of stored
generations from exceeding the user-specified limit.
Deleted files may be later undeleted. Archives may be
packed to recover space occupied by deleted files.
All commands assume that the archive name ends with the
characters .zoo unless a different extension is supplied.
Novice commands
Novice commands may be abbreviated to a hyphen followed by
at least one command character. Each Novice command works
in two stages. First, the command does its intended work.
Then, if the result was that one or more files were
deleted in the specified archive, the archive is packed.
If packing occurs, the original unpacked archive is always
left behind with an extension of .bak.
No Novice command ever stores the directory prefix of a
file.
The Novice commands are as follows.
-add Adds the specified files to the archive.
-freshen
Adds a specified file to the archive if and only if
an older file by the same name already exists in
the archive.
-delete
Deletes the specified files from the archive.
-update
Adds a specified file to the archive either: if an
older file by the same name already exists in the
archive or: if a file by the same name does not
already exist in the archive.
-extract
Extracts the specified files from the archive. If
no file is specified all files are extracted.
-move Equivalent to -add except that source files are
deleted after addition.
-print Equivalent to -extract except that extracted data
are sent to standard output.
-list Gives information about the specified archived
files including any attached comments. If no files
are specified all files are listed. Deleted files
are not listed.
-test Equivalent to -extract except that the extracted
data are not saved but any errors encountered are
reported.
-comment
Allows the user to add or update comments attached
to archived files. When prompted, the user may:
type a carriage return to skip the file, leaving
any current comment unchanged; or type a (possibly
null) comment of up to 32,767 characters terminated
by /end (case-insensitive) on a separate line; or
type the end-of-file character (normally control D)
to skip all remaining files.
-delete
Deletes the specified files.
The correspondence between Novice and Expert commands is as follows.
Novice Equivalent
Command Description Expert Command
-------------------------------------------------------------
-add add files to archive aP:
-extract extract files from archive x
-move move files to archive aMP:
-test test archive integrity xNd
-print extract files to standard output xp
-delete delete files from archive DP
-list list archive contents VC
-update add new or newer files aunP:
-freshen by add newer files auP:
-comment add comments to files c
Expert commands
The general format of expert commands is:
zoo {acfDeghHlLPTuUvVx}[aAcCdEfghImMnNoOpPqSu1:/.@n+-=]
archive [file] ...
The characters enclosed within {} are commands. Choose
any one of these. The characters enclosed within [] just
to the right of the {} are modifiers and zero or more of
these may immediately follow the command character. All
combinations of command and modifier characters may not be
valid.
Files are added to an archive with the command:
zoo {au}[cfhIMnPqu:+-] archive [file] ...
Command characters are:
a Add each specified file to archive. Any already-
archived copy of the file is deleted if this is
necessary to avoid exceeding the user-specified
limit on the number of generations of the file to
maintain in the archive.
u Do an update of the archive. A specified file is
added to the archive only if a copy of it is
already in the archive and the copy being added is
newer than the copy already in the archive.
The following modifiers are specific to these commands.
M Move files to archive. This makes zoo delete
(unlink) the original files after they have been
added to the archive. Files are deleted after
addition of all files to the archive is complete
and after any requested packing of the archive has
been done, and only if zoo detected no errors.
n Add new files only. A specified file is added only
if it isn't already in the archive.
h Use the high performance compression algorithm.
This option may be used with either the add (a) or
filter (f) commands to gain extra compression at
the expense of using somewhat more processor time.
Extracting files compressed with the method is usu-
ally slightly faster than those saved with the
default method.
P Pack archive after files have been added.
u Applied to the a command, this modifier makes it
behave identically to the u command.
The combination of the n modifier with the u modi-
fier or u command causes addition of a file to the
archive either if the file is not already in the
archive, or if the file is already in the archive
but the archived copy is older than the copy being
added.
: Do not store directory names. In the absence of
this modifier zoo stores the full pathname of each
archived file.
I Read filenames to be archived from standard input.
Zoo will read its standard input and assume that
each line of text contains a filename. Under Ami-
gaDOS and the **IX family, the entire line is used.
Under MS-DOS and VAX/VMS, zoo assumes that the
filename is terminated by a blank, tab, or newline;
thus it is permissible for the line of text to con-
tain more than one field separated by white space,
and only the first field will be used.
Under the **IX family of operating systems, zoo can
be used as follows in a pipeline:
find . -print | zoo aI sources
If the I modifier is specified, no filenames may be
supplied on the command line itself.
+,- These modifiers take effect only if the a command
results in the creation of a new archive. + causes
any newly-created archive to have generations
enabled. - is provided for symmetry and causes any
newly-created archive to have generations disabled;
this is also the default if neither + nor - is
specified.
Files are extracted from an archive with the command:
zoo {ex}[dNoOpqS./@] archive [file] ...
The e and x commands are synonymous. If no file was spec-
ified, all files are extracted from the archive.
The following modifiers are specific to the e and x com-
mands:
N Do not save extracted data but report any errors
encountered.
O Overwrite files. Normally, if a file being
extracted would overwrite an already-existing file
of the same name, zoo asks you if you really want
to overwrite it. You may answer the question with
`y', which means yes, overwrite; or `n', which
means no, don't overwrite; or `a', which means
assume the answer is `y' for this and all subse-
quent files. The O modifier makes zoo assume that
files may always be overwritten. Neither answering
the question affirmatively nor using O alone will
cause read-only files to be overwritten.
On **IX systems, however, doubling this modifier as
OO will force zoo to unconditionally overwrite any
read-protected files with extracted files if it can
do so.
The O, N, and p modifiers are mutually exclusive.
S Supersede newer files on disk with older extracted
files. Unless this modifier is used, zoo will not
overwrite a newer existing file with an older
extracted file.
o This is equivalent to the O modifier if and only if
it is given at least twice. It is otherwise
ignored.
p Pipe extracted data to standard output. Error mes-
sages are piped to standard output as well. How-
ever, if a bad CRC is detected, an error message is
sent both to standard error and to standard output.
/ Extract to original pathname. Any needed directo-
ries must already exist. In the absence of this
modifier all files are extracted into the current
directory. If this modifier is doubled as //,
required directories need not exist and are created
if necessary.
The management of multiple generations of archived files
is done with the commands:
zoo gl[Aq]{+-=}number archive files ..
zoo gc[q]{+-=}number archive files ..
zoo gA[q]- archive
zoo gA[q]+ archive
The first form, gl, adjusts the generation limit of
selected files by the specified value. If the form =n is
used, where n is a decimal number, this sets the genera-
tion limit to the specified value. If + or - are used in
placed of = the effect is to increment or decrement the
generation limit by the specified value. For example, the
command
zoo gl=5 xyz :
sets the generation limit of each file in the archive
xyz.zoo to a value of 5. The command
zoo gl-3 xyz :
decrements the generation limit of each file in the
archive to 3 less than it currently is.
If the A modifier is used, the archive-wide generation
limit is adjusted instead.
The number of generations of a file maintained in an
archive is limited by the file generation limit, or the
archive generation limit, whichever is lower. As a spe-
cial case, a generation limit of 0 stands for no limit.
Thus the default file generation limit of 0 and archive
generation limit of 3 limits the number of generations of
each file in a newly-created archive to three.
The generation limit specified should be in the range 0
through 15; any higher numbers are interpreted modulo 16.
The second form of the command, using gc, adjusts the gen-
eration count of selected files. Each file has a genera-
tion count of 1 when it is first added to an archive.
Each time a file by the same name is added again to an
archive, it receives a generation count that is one higher
than the highest generation count of the archived copy of
the file. The permissible range of generation counts is 1
through 65535. If repeated manipulations of an archive
result in files having very high generation counts, they
may be set back to lower numbers with the gc command. The
syntax of the command is analogous to the syntax of the gl
command, except that the A modifier is not applicable to
the gc command.
The third form, gA-, disables generations in an archive.
Generations are off when an archive is first created, but
may be enabled with the fourth form of the command, gA+.
When generations are disabled in an archive, zoo will not
display generation numbers in archive listings or maintain
multiple generations. Generations can be re-enabled at
any time, though manipulation of an archive with repeated
interspersed gA- and gA+ commands may result in an archive
whose behavior is not easily understandable.
Archived files are listed with the command:
zoo {lLvV}[aAcCdfgmqvV@/1+-] archive[.zoo] [file] ...
l Information presented includes the date and time of
each file, its original and current (compressed)
sizes, and the percentage size decrease due to com-
pression (labelled CF or compression factor). If a
file was added to the archive in a different time-
zone, the difference between timezones is shown in
hours as a signed number. As an example, if the
difference is listed as +3, this means that the
file was added to the archive in a timezone that is
3 hours west of the current timezone. The file
time listed is, however, always the original times-
tamp of the archived file, as observed by the user
who archived the file, expressed as that user's
local time. (Timezone information is stored and
displayed only if the underlying operating system
knows about timezones.)
If no filename is supplied all files are listed
except deleted files.
Zoo selects which generation(s) of a file to list
according to the following algorithm.
If no filename is supplied, only the latest genera-
tion of each file is listed. If any filenames are
specified, and a generation is specified for an
argument, only the requested generation is listed.
If a filename is specified ending with the genera-
tion character (`:' or `;'), all generations of
that file are listed. Thus a filename argument of
the form zoo.c will cause only the latest genera-
tion of zoo.c to be listed; an argument of the
form zoo.c:4 will cause generation 4 of zoo.c to be
listed; and an argument of the form zoo.c: or
zoo.c:* will cause all generations of zoo.c to be
listed.
L This is similar to the l command except that all
supplied arguments must be archives and all non-
deleted generations of all files in each archive
appear in the listing.
On **IX systems, on which the shell expands argu-
ments, if multiple archives are to be listed, the L
command must be used. On other systems (VAX/VMS,
AmigaDOS, MSDOS) on which wildcard expansion is
done internally by zoo, wildcards may be used in
the archive name, and a multiple archive listing
obtained, using the l command.
v This causes any comment attached to the archive to
be listed in addition to the other information.
V This causes any comment attached to the archive and
also any comment attached to each file to be
listed.
Both the V and v command characters can also be
used as modifiers to the l and L commands.
In addition to the general modifiers described later, the
following modifiers can be applied to the archive list
commands.
a This gives a single-line format containing both
each filename and the name of the archive, sorted
by archive name. It is especially useful with the
L command, since the result can be further sorted
on any field to give a master listing of the entire
contents of a set of archives.
A This causes any comment attached to the archive to
be listed.
g This modifier causes file generation information to
be listed about the archive. For each file listed,
the user-specified generation limit, if any, is
listed. For example, `3g' for a file means that
the user wants no more than three generations of
the file to be kept. In archives created by older
versions of zoo, the listing will show `-g', mean-
ing that no generation information is kept and mul-
tiple generations of the file are not being main-
tained.
In addition to the generation information for each
file, the archive-wide generation limit, if any, is
shown at the end of the listing. If generations
have been disabled by the user, this is so indi-
cated, for example:
Archive generation limit is 3 (generations off).
For more information about generations see the
description of the g command.
m This modifier is currently applicable to **IX sys-
tems only. It causes the mode bits (file protec-
tion code) of each file to be listed as a three-
digit octal number. Currently zoo preserves only
the lowest nine mode bits. Their meanings are as
described in the **IX documentation for the
chmod(1) command.
C This modifier causes the stored cyclic redundancy
code (CRC) for each archived file to be shown as a
four-digit hexadecimal number.
1 This forces one filename to be listed per line. It
is most useful in combination with the f modifier.
/ This forces any directory name to be always listed,
even in fast columnized listings that do not nor-
mally include any directory names.
+,- The - modifier causes trailing generation numbers
to be omitted from filenames. The + modifier
causes the trailing generation numbers to be shown,
which is also the default if neither - nor + is
specified.
Files may be deleted and undeleted from an archive with
the following commands:
zoo {DU}[Pq1] archive file ...
The D command deletes the specified files and the U com-
mand undeletes the specified files. The 1 modifier (the
digit one, not the letter ell) forces deletion or undele-
tion of at most one file. If multiple instances of the
same file exist in an archive, use of the 1 modifier may
allow selective extraction of one of these.
Comments may be added to an archive with the command:
zoo c[A] archive
Without the modifier A, this behaves identically to the
-comment command. With the modifier A, the command serves
to add or update the comment attached to the archive as a
whole. This comment may be listed with the lA, LA, v, and
V commands. Applying the cA command to an archive that
was created with an older version of zoo will result in an
error message requesting that the user first pack the
archive with the P command. This reorganizes the archive
and creates space for the archive comment.
The timestamp of an archive may be adjusted with the com-
mand:
zoo T[q] archive
Zoo normally attempts to maintain the timestamp of an
archive to reflect the age of the newest file stored in
it. Should the timestamp ever be incorrect it can be
fixed with the T command.
An archive may be packed with the command:
zoo P[EPq] archive
If the backup copy of the archive already exists, zoo will
refuse to pack the archive unless the P modifier is also
given. The E modifier causes zoo not to save a backup
copy of the original archive after packing. A unique tem-
porary file in the current directory is used to initially
hold the packed archive. This file will be left behind if
packing is interrupted or if for some reason this file
cannot be renamed to the name of the original archive when
packing is complete.
Packing removes any garbage data appended to an archive
because of Xmodem file transfer and also recovers any
wasted space remaining in an archive that has been fre-
quently updated or in which comments were replaced. Pack-
ing also updates the format of any archive that was cre-
ated by an older version of zoo so that newer features
(e.g. archive-wide generation limit, archive comment)
become fully available.
Zoo can act as a pure compression or uncompression filter,
reading from standard input and writing to standard out-
put. This is achieved with the command:
zoo f{cu}[h]
where c specifies compression, u specifies uncompression,
and h used in addition requests the high-performance com-
pression be used. A CRC value is used to check the
integrity of the data. The compressed data stream has no
internal archive structure and contains multiple files
only if the input data stream was already structured, as
might be obtained, for example, from tar or cpio.
Modem transfers can be speeded up with these commands:
zoo fc < file | sz ... rz | zoo fu > file
General modifiers
The following modifiers are applicable to several com-
mands:
c Applied to the a and u commands, this causes the
user to be prompted for a comment for each file
added to the archive. If the file being added has
replaced, or is a newer generation of, a file
already in the archive, any comment attached to
that file is shown to the user and becomes attached
to the newly-added file unless the user changes it.
Possible user responses are as described for the
-comment command. Applied to the archive list com-
mand l, the c modifier causes the listing of any
comments attached to archived files.
. In conjunction with / or // this modifier causes
any extracted pathname beginning with `/' to be
interpreted relative to the current directory,
resulting in the possible creation of a subtree
rooted at the current directory. In conjunction
with the command P the . modifier causes the
packed archive to be created in the current direc-
tory. This is intended to allow users with limited
disk space but multiple disk drives to pack large
archives.
d Most commands that act on an archive act only on
files that are not deleted. The d modifier makes
commands act on both normal and deleted files. If
doubled as dd, this modifier forces selection only
of deleted files.
f Applied to the a and u commands, the f modifier
causes fast archiving by adding files without com-
pression. Applied to l it causes a fast listing of
files in a multicolumn format.
q Be quiet. Normally zoo lists the name of each file
and what action it is performing. The q modifier
suppresses this. When files are being extracted to
standard output, the q modifier suppresses the
header preceding each file. When archive contents
are being listed, this modifier suppresses any
header and trailer. When a fast columnized listing
is being obtained, this modifier causes all output
to be combined into a single set of filenames for
all archives being listed.
When doubled as qq, this modifier suppresses WARN-
ING messages, and when tripled as qqq, ERROR mes-
sages are suppressed too. FATAL error messages are
never suppressed.
Recovering data from damaged archives
The @ modifier allows the user to specify the exact posi-
tion in an archive where zoo should extract a file from,
allowing damaged portions of an archive to be skipped.
This modifier must be immediately followed by a decimal
integer without intervening spaces, and possibly by a
comma and another decimal integer, giving a command of the
form l@m or l@m,n (to list archive contents) or x@m or
x@m,n (to extract files from an archive). Listing or
extraction begin at position m in the archive. The value
of m must be the position within the archive of an undam-
aged directory entry. This position is usually obtained
from fiz(1) version 2.0 or later.
If damage to the archive has shortened or lengthened it,
all positions within the archive may be changed by some
constant amount. To compensate for this, the value of n
may be specified. This value is also usually obtained
from fiz(1). It should be the position in the archive of
the file data corresponding to the directory entry that
has been specified with m. Thus if the command x@456,575
is given, it will cause the first 456 bytes of the archive
to be skipped and extraction to begin at offset 456; in
addition, zoo will attempt to extract the file data from
position 575 in the archive instead of the value that is
found in the directory entry read from the archive. For
example, here is some of the output of fiz when it acts on
a damaged zoo archive:
****************
2526: DIR [changes] ==> 95
2587: DATA
****************
3909: DIR [copyrite] ==> 1478
3970: DATA
4769: DATA
****************
In such output, DIR indicates where fiz found a directory
entry in the archive, and DATA indicates where fiz found
file data in the archive. Filenames located by fiz are
enclosed in square brackets, and the notation "==> 95"
indicates that the directory entry found by fiz at posi-
tion 2526 has a file data pointer to position 95. (This
is clearly wrong, since file data always occur in an
archive after their directory entry.) In actuality, fiz
found file data at positions 2587, 3970, and 4769. Since
fiz found only two directory entries, and each directory
entry corresponds to one file, one of the file data posi-
tions is an artifact.
In this case, commands to try giving to zoo might be
x@2526,2587 (extract beginning at position 2526, and get
file data from position 2587), x@3090,3970 (extract at
3090, get data from 3970) and x@3909,4769 (extract at
3909, get data from 4769). Once a correctly-matched
directory entry/file data pair is found, zoo will in most
cases synchronize with and correctly extract all files
subsequently found in the archive. Trial and error should
allow all undamaged files to be extracted. Also note that
self-extracting archives created using sez (the Self-
Extracting Zoo utility for MS-DOS), which are normally
executed on an MS-DOS system for extraction, can be
extracted on non-MSDOS systems using zoo's damaged-archive
recovery method using the @ modifier.
Wildcard handling
Under the **IX family of operating systems, the shell nor-
mally expands wildcards to a list of matching files.
Wildcards that are meant to match files within an archive
must therefore be escaped or quoted. When selecting files
to be added to an archive, wildcard conventions are as
defined for the shell. When selecting files from within
an archive, wildcard handling is done by zoo as described
below.
Under MS-DOS and AmigaDOS, quoting of wildcards is not
needed. All wildcard expansion of filenames is done by
zoo, and wildcards inside directory names are expanded
only when listing or extracting files but not when adding
them.
The wildcard syntax interpreted by zoo is limited to the
following characters.
* Matches any sequence of zero or more characters.
Matches any single character.
Arbitrary combinations of * and ? are allowed.
/ If a supplied pattern contains a slash anywhere in
it, then the slash separating any directory prefix
from the filename must be matched explicitly. If a
supplied pattern contains no slashes, the match is
selective only on the filename.
c-c Two characters separated by a hyphen specify a
character range. All filenames beginning with
those characters will match. The character range
is meaningful only by itself or preceded by a
directory name. It is not specially interpreted if
it is part of a filename.
: and ;
These characters are used to separate a filename
from a generation number and are used when select-
ing specific generations of archived files. If no
generation character is used, the filename speci-
fied matches only the latest generation of the
file. If the generation character is specified,
the filename and the generation are matched inde-
pendently by zoo's wildcard mechanism. If no gen-
eration is specified following the : or ; charac-
ter, all generations of that file will match. As a
special case, a generation number of 0 matches only
the latest generation of a file, while ^0 matches
all generations of a file except the latest one.
If no filename is specified preceding the genera-
tion character, all filenames will match. As a
corollary, the generation character by itself
matches all generations of all files.
MS-DOS users should note that zoo does not treat the dot
as a special character, and it does not ignore characters
following an asterisk. Thus * matches all filenames; *.*
matches filenames containing a dot; *_* matches filenames
containing an underscore; and *z matches all filenames
that end with the character z, whether or not they contain
a dot.
Usage hints
The Novice command set in zoo is meant to provide an
interface with functionality and format that will be
familiar to users of other similar archive utilities. In
keeping with this objective, the Novice commands do not
maintain or use any subdirectory information or allow the
use of zoo's ability to maintain multiple generations of
files. For this reason, users should switch to exclu-
sively using the Expert commands as soon as possible.
Although the Expert command set is quite large, it should
be noted that in almost every case, all legal modifiers
for a command are fully orthogonal. This means that the
user can select any combination of modifiers, and when
they act together, they will have the intuitively obvious
effect. Thus the user need only memorize what each modi-
fier does, and then can combine them as needed without
much further thought.
For example, consider the a command which is used to add
files to an archive. By itself, it simply adds the speci-
fied files. To cause only already-archived files to be
updated if their disk copies have been modified, it is
only necessary to add the u modifier, making the command
au. To cause only new files (i.e., files not already in
the archive) to be added, the n modifier is used to create
the command an. To cause both already-archived files to
be updated and new files to be added, the u and n modi-
fiers can be used together, giving the command aun. Since
the order of modifiers is not significant, the command
could also be anu.
Further, the c modifier can be used to cause zoo to prompt
the user for a comment to attach to each file added. And
the f modifier can cause fast addition (addition without
compression). It should be obvious then that the command
auncf will cause zoo to update already-archived files, add
new files, prompt the user for comments, and do the addi-
tion of files without any compression. Furthermore, if
the user wishes to move files to the archive, i.e., delete
the disk copy of each file after it is added to the
archive, it is only necessary to add the M modifier to the
command, so it becomes auncfM. And if the user also
wishes to cause the archive to be packed as part of the
command, thus recovering space from any files that are
replaced, the command can be modified to auncfMP by adding
the P modifier that causes packing.
Similarly, the archive listing commands can be built up by
combining modifiers. The basic command to list the con-
tents of an archive is l. If the user wants a fast colum-
nized listing, the f modifier can be added to give the lf
command. Since this listing will have a header giving the
archive name and a trailer summarizing interesting infor-
mation about the archive, such as the number of deleted
files, the user may wish to "quieten" the listing by sup-
pressing these; the relevant modifier is q, which when
added to the command gives lfq. If the user wishes to see
the **IX mode (file protection) bits, and also information
about multiple generations, the modifiers m (show mode
bits) and g (show generation information) can be added,
giving the command lfqmg. If the user also wishes to see
an attached archive comment, the modifier A (for archive)
will serve. Thus the command lfqmgA will give a fast
columnized listing of the archive, suppressing any header
and trailer, showing mode bits and generation information,
and showing any comment attached to the archive as a
whole. If in addition individual comments attached to
files are also needed, simply append the c modifier to the
command, making it lfqmgAc. The above command will not
show any deleted files, however; to see them, use the d
modifier, making the command lfqmgAcd (or double it as in
lfqmgAcdd if only the deleted files are to be listed).
And if the user also wishes to see the CRC value for each
file being listed, the modifier C will do this, as in the
command lfqmgAcdC, which gives a fast columnized listing
of all files, including deleted files, showing any archive
comment and file comments, and file protection codes and
generation information, as well as the CRC value of each
file.
Note that the above command lfqmgAcdC could also be abbre-
viated to VfqmgdC because the command V is shorthand for
lcA (archive listing with all comments shown). Similarly
the command v is shorthand for lA (archive listing with
archive comment shown). Both V and v can be used as modi-
fiers to any of the other archive listing commands.
Generations
By default, zoo assumes that only the latest generation of
a specified file is needed. If generations other than the
latest one need to be selected, this may be done by speci-
fying them in the filename. For example, the name stdio.h
would normally refer to the latest generation of the file
stdio.h stored in a zoo archive. To get an archive list-
ing showing all generations of stdio.h in the archive, the
specification stdio.h:* could be used (enclosed in single
quotes if necessary to protect the wildcard character *
from the shell). Also, stdio.h:0 selects only the latest
generation of stdio.h, while stdio.h:^0 selects all gener-
ations except the latest one. The : character here sepa-
rates the filename from the generation number, and the
character * is a wildcard that matches all possible gener-
ations. For convenience, the generation itself may be
left out, so that the name stdio.h: (with the : but with-
out a generation number or a wildcard) matches all genera-
tions exactly as stdio.h:* does.
If a generation is specified but no filename is present,
as in :5, :*, or just :, all filenames of the specified
generation will be selected. Thus :5 selects generation 5
of each file, and :* and : select all generations of all
files.
It is important to note that zoo's idea of the latest gen-
eration of a file is not based upon searching the entire
archive. Instead, whenever zoo adds a file to an archive,
it is marked as being the latest generation. Thus, if the
latest generation of a file is deleted, then no generation
of that file is considered the latest any more. This can
be surprising to the user. For example, if an archive
already contains the file stdio.h:5 and a new copy is
added, appearing in the archive listing as stdio.h:6, and
then stdio.h:6 is deleted, the remaining copy stdio.h:5
will no longer be considered to be the latest generation,
and the file stdio.h:5, even if undeleted, will no longer
appear in an archive listing unless generation 5 (or every
generation) is specifically requested. This behavior will
likely be improved in future releases of zoo.
FILES
xXXXXXX - temporary file used during packing
archive_name.bak - backup of archive
SEE ALSO
compress(1), fiz(1)
BUGS
When files are being added to an archive on a non-MS-DOS
system, it is possible for zoo to fail to detect a full
disk and hence create an invalid archive. This bug will
be fixed in a future release.
Files with generation counts that wrap around from 65535
to 1 are not currently handled correctly. If a file's
generation count reaches a value close to 65535, it should
be manually set back down to a low number. This may be
easily done with a command such as gc-65000, which sub-
tracts 65000 from the generation count of each specified
file. This problem will be fixed in a future release.
Although zoo on **IX systems preserves the lowest nine
mode bits of regular files, it does not currently do the
same for directories.
Currently zoo's handling of the characters : and ; in
filenames is not robust, because it interprets these to
separate a filename from a generation number. A quoting
mechanism will eventually be implemented.
Standard input cannot be archived nor can a created
archive be sent to standard output. Spurious error mes-
sages may appear if the filename of an archive is too
long.
Since zoo never archives any file with the same name as
the archive or its backup (regardless of any path pre-
fixes), care should be taken to make sure that a file to
be archived does not coincidentally have the same name as
the archive it is being added to. It usually suffices to
make sure that no file being archived is itself a zoo
archive. (Previous versions of zoo sometimes tried to add
an archive to itself. This bug now seems to be fixed.)
Only regular files are archived; devices and empty direc-
tories are not. Support for archiving empty directories
and for preserving directory attributes is planned for the
near future.
Early versions of MS-DOS have a bug that prevents "." from
referring to the root directory; this leads to anomalous
results if the extraction of paths beginning with a dot is
attempted.
VAX/VMS destroys case information unless arguments are
enclosed in double quotes. For this reason if a command
given to zoo on a VAX/VMS system includes any uppercase
characters, it must be enclosed in double quotes. Under
VAX/VMS, zoo does not currently restore file timestamps;
this will be fixed as soon as I figure out RMS extended
attribute blocks, or DEC supplies a utime() function,
whichever occurs first. Other VMS bugs, related to file
structures, can often be overcome by using the program
bilf.c that is supplied with zoo.
It is not currently possible to create a zoo archive con-
taining all zoo archives that do not contain themselves.
DIAGNOSTICS
Error messages are intended to be self-explanatory and are
divided into three categories. WARNINGS are intended to
inform the user of an unusual situation, such as a CRC
error during extraction, or -freshening of an archive con-
taining a file newer than one specified on the command
line. ERRORS are fatal to one file, but execution contin-
ues with the next file if any. FATAL errors cause execu-
tion to be aborted. The occurrence of any of these causes
an exit status of 1. Normal termination without any
errors gives an exit status of 0. (Under VAX/VMS, how-
ever, to avoid an annoying message, zoo always exits with
an error code of 1.)
COMPATIBILITY
All versions of zoo on all systems are required to create
archives that can be extracted and listed with all ver-
sions of zoo on all systems, regardless of filename and
directory syntax or archive structure; furthermore, any
version of zoo must be able to fully manipulate all
archives created by all lower-numbered versions of zoo on
all systems. So far as I can tell, this upward compati-
bility (all manipulations) and downward compatiblity
(ability to extract and list) is maintained by zoo ver-
sions up to 2.01. Version 2.1 adds the incompatibility
that if high-performance compression is used, earlier ver-
sions cannot extract files compressed with version 2.1.
This is the only incompatibility that is permissible. You
are forbidden, with the force of copyright law, to create
from the zoo source code any derivative work that violates
this compatibility goal, whether knowingly or through neg-
ligence. If any violation of this compatibility goal is
observed, this should be considered a serious problem and
reported to me.
CHANGES
Here is a list of changes occurring from version 1.50 to
version 2.01. In parentheses is given the version in
which each change occurred.
- (1.71) New modifiers to the list commands permit
optional suppression of header and trailer informa-
tion, inclusion of directory names in columnized
listings, and fast one-column listings.
- (1.71) Timezones are handled.
- (1.71) A bug was fixed that had made it impossible
to individually update comments for a file whose
name did not correspond to MS-DOS format.
- (1.71) A change was made that now permits use of
the shared library on the **IX PC.
- (1.71) VAX/VMS is now supported reasonably well.
- (2.00) A comment may now be attached to the archive
itself.
- (2.00) The OO option allows forced overwriting of
read-only files.
- (2.00) Zoo will no longer extract a file if a newer
copy already exists on disk; the S option will
override this.
- (2.00) File attributes are preserved for **IX sys-
tems.
- (2.00) Multiple generations of the same file are
supported.
- (2.00) Zoo will now act as a compression or decom-
pression filter on a stream of data and will use a
CRC value to check the integrity of a data stream
that is uncompressed.
- (2.00) A bug was fixed that caused removal of a
directory link if files were moved to an archive by
the superuser on a **IX system.
- (2.00) The data recovery modifier @ was greatly
enhanced. Self-extracting archives created for MS-
DOS systems can now be extracted by zoo on any sys-
tem with help from fiz(1).
- (2.01) A bug was fixed that had caused the first
generation of a file to sometimes unexpectedly show
up in archive listings.
- (2.01) A bug was fixed that had caused the MS-DOS
version to silently skip files that could not be
extracted because of insufficient disk space.
- (2.01) A bug was fixed that had sometimes made it
impossible to selectively extract a file by speci-
fying its name, even though all files could be
extracted from the archive by not specifying any
filenames. This occurred when a file had been
archived on a longer-filename system (e.g. Amiga-
DOS) and extraction was attempted on a shorter-
filename system (e.g. MS-DOS).
- (2.01) A change was made that will make zoo pre-
serve the mode (file protection) of a zoo archive
when it is packed. This is effective only if zoo
is compiled to preserve and restore file
attributes. Currently this is so only for **IX
systems.
- (2.01) A bug was fixed that had caused an update of
an archive to not always add all newer files.
- (2.01) Blanks around equal signs in commands given
to "make" were removed from the mk* scripts for
better compatiblity with more **IX implementations
including Sun's.
- (2.1) Compression is now greatly improved if the
"h" option is used.
- (2.1) The default behavior is to preserve full
pathnames during extraction.
- (2.1) On some systems, extraction of files using
the older (default) compression method is greatly
speeded up.
- (2.1) Extended multiscreen help is available.
- (2.1) Memory allocation is improved, so that the
MS-DOS version will not prematurely abort when
updating a large archive.
- (2.1) The VAX/VMS version preserves file timestamps
during extraction.
- (2.1) The default archive-wide generation limit,
when generations are enabled, is 3.
FUTURE DIRECTIONS
A revised version of zoo is in the works that will be able
to write newly-created archives to standard output and
will support multivolume archives. It will be upward and
downward compatible with this version of zoo.
ACKNOWLEDGEMENTS
The zoo archiver was initially developed using Microsoft C
3.0 on a PC clone manufactured by Toshiba of Japan and
almost sold by Xerox. Availability of the following sys-
tems was helpful in achieving portability: Paul Homchick's
Compaq running Microport System V/AT; The Eskimo BBS
somewhere in Oregon running Xenix/68000; Greg Laskin's
system 'gryphon' which is an Intel 310 running Xenix/286;
Ball State University's AT&T 3B2/300, UNIX PC, and
VAX-11/785 (4.3BSD and VAX/VMS) systems. In addition J.
Brian Waters provided feedback to help me make the code
compilable on his Amiga using Manx/Aztec C. The exe-
cutable version 2.0 for MS-DOS is currently compiled with
Borland's Turbo C++ 1.0.
Thanks are due to the following people and many others too
numerous to mention.
J. Brian Waters <jbwaters@bsu-cs.bsu.edu>, who has worked
diligently to port zoo to AmigaDOS, created Amiga-specific
code, and continues keeping it updated.
Paul Homchick <rutgers!cgh!paul>, who provided numerous
detailed reports about some nasty bugs.
Bill Davidsen <davidsen@crdos1.crd.ge.com>, who provided
numerous improvements to this manual, contributed multi-
screen help, and provided many useful bug reports, bug
fixes, code improvements, and suggestions.
Mark Alexander <amdahl!drivax!alexande>, who provided me
with some bug fixes.
Haruhiko Okumura, who wrote the ar archiver and some
excellent compression code, which I adapted for use in
zoo.
Randal L. Barnes <rlb@skyler.mavd.honeywell.com>, who
(with Randy Magnuson) wrote the code to support the
preservation of file timestamps under VAX/VMS.
Raymond D. Gardner, who contributed replacement uncompres-
sion code that on some systems is twice as fast as the
original.
Greg Yachuk and Andre Van Dalen, who independently modi-
fied MS-DOS zoo to support multivolume archives. (This
support is not yet in this official release.)
AUTHOR
Rahul Dhesi
Hurricane Electric Internet Services
Copyright (C) 1998
Hurricane Electric.
All Rights Reserved.