ZOO(1)ZOO(1)NAMEzoo - manipulate archives of files in compressed form
SYNOPSISzoo {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 algorithm that gives space sav‐
ings 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 dam‐
aged portion and locating undamaged data with the help of fiz(1).
This documentation is for version 2.1. Changes from previous 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 specified 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 com‐
mand 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 orig‐
inal 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 proces‐
sor time. Extracting files compressed with the method is usually
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 identi‐
cally to the u command.
The combination of the n modifier with the u modifier or u com‐
mand 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 con‐
tains a filename. Under AmigaDOS 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 contain 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 specified, all
files are extracted from the archive.
The following modifiers are specific to the e and x commands:
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 subsequent 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 messages are
piped to standard output as well. However, 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 directories must
already exist. In the absence of this modifier all files are
extracted into the current directory. If this modifier is dou‐
bled 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 num‐
ber, this sets the generation 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, which‐
ever is lower. As a special case, a generation limit of 0 stands for
no limit. Thus the default file generation limit of 0 and archive gen‐
eration 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 generation count
of selected files. Each file has a generation 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 com‐
mand.
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 compression (labelled CF or compression
factor). If a file was added to the archive in a different
timezone, 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 time‐
zone that is 3 hours west of the current timezone. The file
time listed is, however, always the original timestamp 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 generation of each
file is listed. If any filenames are specified, and a genera‐
tion 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 generation 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 argu‐
ments 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 arguments, if multi‐
ple 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 modi‐
fiers 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', meaning that no generation
information is kept and multiple generations of the file are not
being maintained.
In addition to the generation information for each file, the ar‐
chive-wide generation limit, if any, is shown at the end of the
listing. If generations have been disabled by the user, this is
so indicated, 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 systems only. It
causes the mode bits (file protection 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 num‐
ber.
1 This forces one filename to be listed per line. It is most use‐
ful in combination with the f modifier.
/ This forces any directory name to be always listed, even in fast
columnized listings that do not normally 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 command undeletes
the specified files. The 1 modifier (the digit one, not the letter
ell) forces deletion or undeletion 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 com‐
mand. 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 ar‐
chive 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 ar‐
chive comment.
The timestamp of an archive may be adjusted with the command:
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 temporary 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 Xmo‐
dem file transfer and also recovers any wasted space remaining in an
archive that has been frequently updated or in which comments were
replaced. Packing 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 output. 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 compression 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 commands:
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
command 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 sub‐
tree rooted at the current directory. In conjunction with the
command P the . modifier causes the packed archive to be cre‐
ated in the current directory. 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 ar‐
chiving by adding files without compression. 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 con‐
tents 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 WARNING messages,
and when tripled as qqq, ERROR messages are suppressed too.
FATAL error messages are never suppressed.
Recovering data from damaged archives
The @ modifier allows the user to specify the exact position in an ar‐
chive where zoo should extract a file from, allowing damaged portions
of an archive to be skipped. This modifier must be immediately fol‐
lowed 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 ar‐
chive. The value of m must be the position within the archive of an
undamaged 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 compen‐
sate 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 [copyright] ==> 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 nota‐
tion "==> 95" indicates that the directory entry found by fiz at
position 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 positions 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 exe‐
cuted on an MS-DOS system for extraction, can be extracted on non-MSDOS
systems using zoo's damaged-archive recovery method using the @ modi‐
fier.
Wildcard handling
Under the **IX family of operating systems, the shell normally 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 ar‐
chive, 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 genera‐
tion number and are used when selecting specific generations of
archived files. If no generation character is used, the file‐
name specified matches only the latest generation of the file.
If the generation character is specified, the filename and the
generation are matched independently by zoo's wildcard mecha‐
nism. If no generation is specified following the : or ; char‐
acter, all generations of that file will match. As a special
case, a generation number of 0 matches only the latest genera‐
tion of a file, while ^0 matches all generations of a file
except the latest one. If no filename is specified preceding
the generation character, all filenames will match. As a corol‐
lary, 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 simi‐
lar archive utilities. In keeping with this objective, the Novice com‐
mands 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 exclusively using the Expert com‐
mands 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 modifier
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 specified 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 com‐
mand au. To cause only new files (i.e., files not already in the ar‐
chive) 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 modifiers 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 addition
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 contents of an archive is l.
If the user wants a fast columnized 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 informa‐
tion about the archive, such as the number of deleted files, the user
may wish to "quieten" the listing by suppressing 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 informa‐
tion 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 modi‐
fier 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 modi‐
fier to the command, making it lfqmgAc. The above command will not
show any deleted files, however; to see them, use the d modifier, mak‐
ing 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 abbreviated 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 modifiers 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 specifying 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 listing
showing all generations of stdio.h in the archive, the specification
stdio.h:* could be used (enclosed in single quotes if necessary to pro‐
tect the wildcard character * from the shell). Also, stdio.h:0 selects
only the latest generation of stdio.h, while stdio.h:^0 selects all
generations except the latest one. The : character here separates the
filename from the generation number, and the character * is a wildcard
that matches all possible generations. 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 generations 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 gen‐
erations of all files.
It is important to note that zoo's idea of the latest generation 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 genera‐
tion. 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 ar‐
chive 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 ALSOcompress(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 num‐
ber. This may be easily done with a command such as gc-65000, which
subtracts 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 gen‐
eration 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 messages 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 prefixes), 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. (Previ‐
ous 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 directories 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 dou‐
ble 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 containing 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 -freshen‐
ing of an archive containing a file newer than one specified on the
command line. ERRORS are fatal to one file, but execution continues
with the next file if any. FATAL errors cause execution to be aborted.
The occurrence of any of these causes an exit status of 1. Normal ter‐
mination without any errors gives an exit status of 0. (Under VAX/VMS,
however, 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 versions of zoo on all systems,
regardless of filename and directory syntax or archive structure; fur‐
thermore, any version of zoo must be able to fully manipulate all ar‐
chives created by all lower-numbered versions of zoo on all systems.
So far as I can tell, this upward compatibility (all manipulations) and
downward compatibility (ability to extract and list) is maintained by
zoo versions up to 2.01. Version 2.1 adds the incompatibility that if
high-performance compression is used, earlier versions cannot extract
files compressed with version 2.1.
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 sup‐
pression of header and trailer information, inclusion of direc‐
tory 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 individu‐
ally 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 systems.
- (2.00) Multiple generations of the same file are supported.
- (2.00) Zoo will now act as a compression or decompression 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 system 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 specifying 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. AmigaDOS) and extraction was
attempted on a shorter-filename system (e.g. MS-DOS).
- (2.01) A change was made that will make zoo preserve 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 compatibility 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 genera‐
tions 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 systems was helpful in achieving porta‐
bility: Paul Homchick's Compaq running Microport System V/AT; The
Eskimo BBS somewhere in Oregon running Xenix/68000; Greg Laskin's sys‐
tem 'gryphon' which is an Intel 310 running Xenix/286; Ball State Uni‐
versity'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 executable
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 keep‐
ing 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 multiscreen 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 compres‐
sion code, which I adapted for use in zoo.
Randal L. Barnes <rlb@skyler.mavd.honeywell.com>, who (with Randy Mag‐
nuson) wrote the code to support the preservation of file timestamps
under VAX/VMS.
Raymond D. Gardner, who contributed replacement uncompression code that
on some systems is twice as fast as the original.
Greg Yachuk and Andre Van Dalen, who independently modified MS-DOS zoo
to support multivolume archives. (This support is not yet in this
official release.)
AUTHOR
Rahul Dhesi
7th Edition July 7, 1991 ZOO(1)
