shar program
unshar program
Copyright (C) 1994 Free Software Foundation, Inc.
Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies.
Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one.
Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions, except that this permission notice may be stated in a translation approved by the Foundation.
GNU shar makes so-called shell archives out of many files,
preparing them for transmission by electronic mail services.
A shell archive is a collection of files that can be unpacked by
/bin/sh. A wide range of features provide extensive flexibility
in manufacturing shars and in specifying shar smartness. For
example, shar may compress files, uuencode binary files, split
long files and construct multi-part mailings, ensure correct unsharing
order, and provide simplistic checksums. See section Invoking the shar program.
GNU unshar scans a set of mail messages looking for the start
of shell archives. It will automatically strip off the mail headers
and other introductory text. The archive bodies are then unpacked by
a copy of the shell. unshar may also process files containing
concatenated shell archives. See section Invoking the unshar program.
GNU shar has a long history. All along this long road, numerous
users contributed various improvements. The file `THANKS', from
the GNU shar distribution, contain all names still having
valid email addresses, as far as we know.
Please help me getting the history straight, for the following
information is approximative. James Gosling wrote the public domain
shar 1.x. William Davidsen rewrote it as shar 2.x.
Warren Tucker brought modifications and called it shar 3.x.
Richard Gumpertz maintained it until 1990. Pinard,
from the public domain shar 3.49, made GNU shar 4.x,
in 1994. Some modules and other code sections were freely borrowed
from other GNU distributions, bringing this shar under the
terms of the GNU General Public License.
Your feedback helps us to make a better and more portable product. Mail suggestions and bug reports (including documentation errors) for these programs to `bug-gnu-utils@prep.ai.mit.edu'.
shar program
The format of the shar command is one of:
shar [ option ] ... file ... shar -S [ option ] ...
In the first form, the file list is given as command arguments. In the
second form, the file list is read from standard input. The resulting
archive is sent to standard output unless the -o option is given.
Options can be given in any order. Some options depend on each other:
the -o option is required if the -l or -L option
is used. The -n option is required if the -a option
is used. Also see -V below.
Some options are special purpose:
--help
--version
-q
--quiet
shar time. Messages are usually issued
on standard error to let the user follow the progress, while making
the archives. This option inhibits these messages.
-p
--intermix-type
-M, -B,
-T, -z and -Z may be embedded, and files to
the right of the option will be processed in the specified mode.
Without the -p option, embedded options would be interpreted
as file names. See section Selecting how files are stocked for more information on these options.
-S
--stdin-file-list
find . -type f -print | shar -S -o /tmp/big.sharIf
-p is specified on the command line, then the options
-M, -B, -T, -z and -Z may be
included in the standard input (on a line separate from file names).
The maximum number of lines of standard input, file names and options,
may not exceed 1024.
-o prefix
--output-prefix=prefix
-l or the -L switches
are used.
When prefix contains any `%' character, prefix is then
interpreted as a sprintf format, which should be able to display
a single decimal number. When prefix does not contain such a
`%' character, the string `.%02d' is internally appended.
-l size
--whole-size-limit=size
-L size
--split-size-limit=size
unshar, used with option -e, to unpack them
all at once. See section Invoking the unshar program.
For people used to saving all the shell archives into a single mail
folder, care must be taken to save them in the appropriate order.
For those having the appropriate tools (like Masanobu Umeda's
rmailsort package for GNU Emacs), shell archives can be saved
in any order, then sorted by increasing date (or send time) before
massive unpacking.
-n name
--archive-name=name
-a switch further down.
-s address
--submitter=address
-s option allows for overriding the email address for the
submitter, for when the default is not appropriate. The automatically
determined address looks like `username@hostname'.
-a
--net-headers
Submitted-by: address Archive-name: name/partnnThe name must be given with the
-n switch. If name
includes a `/', then `/part' isn't used. Thus
`-n xyzzy' produces:
xyzzy/part01 xyzzy/part02while `-n xyzzy/patch' produces:
xyzzy/patch01 xyzzy/patch02and `-n xyzzy/patch01.' produces:
xyzzy/patch01.01 xyzzy/patch01.02
-c
--cut-mark
-T
--text-files
-B
--uuencode
uuencode prior to packing. This
increases the size of the archive. The recipient must have
uudecode in order to unpack.
Use of uuencode is not appreciated by many on the net, because
people like to readily see, by mere inspection of a shell archive,
what it is about.
-M
--mixed-uuencode
-z
--gzip
gzip and uuencode on all files prior to packing.
The recipient must have uudecode and gzip (used with
-d) in order to unpack.
Usage of -z in net shars will cause you to be flamed off
the earth.
-g level
--level-for-gzip=level
-level as a parameter to
gzip. The -g option turns on the -z option
by default. The default value is 9, that is, maximum compression.
-Z
--compress
compress and uuencode on all files prior to packing.
The recipient must have uudecode and compress (used
with -d) in order to unpack. Option -C is a synonymous
for -Z, but is deprecated.
Usage of -Z in net shars will cause you to be flamed off
the earth.
-b bits
--bits-per-code=bits
-bx as a parameter to
compress. The -B option turns on the -Z
option by default. The default value is 12, foreseeing the memory
limitations of some compress programs on smallish systems, at
unshar time.
Transmission of shell archives is not always free of errors. So one
should make consistency checks on the receiving site. A very simple
(and unreliable) method is running the UNIX wc tool on the output
file. This can report the number of characters in the file.
As one can guess this does not catch all errors. Especially changing of
a character value does not change the computed check sum. To achieve
this goal better method were invented and standardized. One very strong
is MD5 (MD = message digests). This is standardized in RFC 1321. The
produced shell scripts do not force the md5sum program to be
installed on the system. This is necessary because it is not yet part
of every UNIX. The program is however not necessary for producing the
shell archive.
-w
--no-character-count
-D
--no-md5-digest
-F
--force-prefix
-B or -Z is used. Normally, the prefix character
is `X'. If the parameter to the -d option starts with
`X', then the prefix character becomes `Y'.
-d string
--here-delimiter=string
-V
--vanilla-operation
echo, test and sed in the unpacking
environment.
The -V disables options offensive to the network cop
(or brown shirt). It also changes the default from mixed mode
-M to text mode -T. Warnings are produced if option
-B, -z, -Z, -p or -M is specified
(any of which does or might require uudecode, gzip or
compress in the unpacking environment).
-P
--no-piping
uudecode, instead of using pipes. This option is mandatory
when you know the unpacking uudecode is unwilling to merely
read its standard input. Richard Marks wrote what is certainly the
most (in)famous of these, for MSDOS :-).
(Here is a side note from the maintainer. Why isnt't this option
the default? In the past history of shar, it was decided
that piping was better, surely because it is less demanding on disk
space, and people seem to be happy with this. Besides, I think
that the uudecode from Richard Marks, on MSDOS, is wrong in
refusing to handle stdin. So far that I remember, he has
the strong opinion that a program without any parameters should
give its --help output. Besides that, should I say, his
uuencode and uudecode programs are full-featured, one
of the most complete set I ever saw. But Richard will not release
his sources, he wants to stay in control.)
-x
--no-check-existing
-x nor
-X is specified, when unpacking itself, the shell archive will
check for and not overwrite existing files (unless -c is passed
as a parameter to the script when unpacking).
-X
--query-user
-X produces shars which will cause problems
with some unshar-style procedures, particularily when used
together with vanilla mode (-V). Use this feature mainly for
archives to be passed among agreeable parties. Certainly, -X
is not for shell archives which are to be submitted to Usenet
or other public networks.
The problem is that unshar programs or procedures often feed
`/bin/sh' from its standard input, thus putting `/bin/sh'
and the shell archive script in competition for input lines. As an
attempt to alleviate this problem, shar will try to detect if
`/dev/tty' exists at the receiving site and will use it to read
user replies. But this does not work in all cases, it may happen that
the receiving user will have to avoid using unshar programs
or procedures, and call /bin/sh directly. In vanilla mode,
using `/dev/tty' is not even attempted.
-m
--no-timestamp
touch commands to restore the file modification
dates when unpacking files from the archive.
When the timestamp relationship is not preserved, some files like
`configure' or `*.info' may be uselessly remade after
unpacking. This is why, when this option is not used, a special
effort is made to restore timestamps,
-Q
--quiet-unshar
unshar time. Disables the inclusion of
comments to be output when the archive is unpacked.
-f
--basename
shar, the substructure of that directory will be
restored whether -f is specified or not.
unshar program
The format of the unshar command is:
unshar [ option ] ... [ file ... ]
Each file is processed in turn, as a shell archive or a collection of shell archives. If no files are given, then standard input is processed instead.
Options:
--version
--help
-d directory
--directory=directory
-c
--overwrite
-f
--force
shar 3.40 and newer) accepts
a -c argument to indicate that existing files should be
overwritten.
The option -f is provided for a more unique interface. Many
programs (such as cp and mv) use this option to trigger
the very same action.
-e
--exit-0
unshar isolates
each different shell archive from the others which have been put in the
same file, unpacking each in turn, from the beginning of the file
towards its end. Its proper operation relies on the fact that many shar
files are terminated by a `exit 0' at the beginning of a line.
Option -e is internally equivalent to -E "exit 0".
-E string
--split-at=string
-e, but it allows you to specify the
string that separates archives if `exit 0' isn't appropriate.
For example, noticing that most `.signatures' have a `--' on
a line right before them, one can sometimes use `--split-at=--'
for splitting shell archives which lack the `exit 0' line at end.
The signature will then be skipped altogether with the headers of
the following message.
Here is a place-holder for many considerations which do not fit elsewhere, while not worth a section for themselves.
Be careful that the output file(s) are not included in the inputs
or shar may loop until the disk fills up. Be particularly
careful when a directory is passed to shar that the output
files are not in that directory (or a subdirectory of that directory).
When a directory is passed to shar, it may be scanned more
than once, to conserve memory. Therefore, one should be careful to
not change the directory contents while shar is running.
No attempt is made to restore the protection and modification dates
for directories, even if this is done by default for files. Thus, if
a directory is given to shar, the protection and modification
dates of corresponding unpacked directory may not match those of
the original.
Use of the -M or -B options will slow down the archive
process. Use of the -z or -Z options may slow the
archive process considerably.
Let us conclude by a showing a few examples of shar usage:
shar *.c > cprog.shar shar -Q *.[ch] > cprog.shar shar -B -l28 -oarc.sh. *.arc shar -f /lcl/src/u*.c > u.sh
The first shows how to make a shell archive out of all C program sources. The second produces a shell archive with all `.c' and `.h' files, which unpacks silently. The third gives a shell archive of all uuencoded `.arc' files, into files `arc.sh.01' through to `arc.sh.nnn'. The last example gives a shell archive which will use only the file names at unpack time.
This document was generated on 7 November 1998 using the texi2html translator version 1.52.