unshar - Man Page

unpack a shar archive


unshar [-flags] [-flag [value]] [--option-name[[=| ]value]] [<file>...]

The operands that this program operates on may be specified either on the command line or read from standard input, one per line. In that input, leading and trailing white space is stripped, blank lines are ignored. Standard input may not be a terminal.


Unshar scans the input files (typically email messages) looking for the start of a shell archive.  If no files are given, then standard input is processed instead.  It then passes each archive discovered through an invocation of the shell program to unpack it.

This program will perform its function for every file named on the command line or every file named in a list read from stdin.  The arguments or input names must be pre-existing files.  The input list may contain comments, which are blank lines or lines beginning with a '#' character.


-d dir, --directory=dir

unpack into the directory dir.

The input file names are relative to the current directory when the program was started.  This option tells unshar to insert a cd <dir> commad at the start of the shar text written to the shell.

-c,  --overwrite

overwrite any pre-existing files.

This option is passed through as an option to the shar file.  Many shell archive scripts accept a -c argument to indicate that existing files should be overwritten.

-f,  --force

This is an alias for the --overwrite option.

-E split-mark, --split-at=split-mark

split input on split-mark lines. The default split-mark for this option is:

exit 0

With this option, unshar isolates each different shell archive from the others which have been placed in the same file, unpacking each in turn, from the beginning of the file to the end.  Its proper operation relies on the fact that many shar files are terminated by a readily identifiable string at the start of the last line.

For example, noticing that most `.signatures' have a double hyphen ("--") on a line right before them, one can then sometimes use --split-at=--.  The signature will then be skipped, along with the headers of the following message.

-e,  --exit-0

split input on "exit 0" lines. This option must not appear in combination with any of the following options: split-at.

Most shell archives end with a line consisting of simply "exit 0". This option is equivalent to (and conflicts with) --split-at="exit 0".

-D,  --debug

debug the shell code.

"set -x" will be emitted into the code the shell interprets.

-h,  --help

Display usage information and exit.

-!,  --more-help

Pass the extended usage information through a pager.

-R [cfgfile], --save-opts [=cfgfile]

Save the option state to cfgfile.  The default is the last configuration file listed in the Option Presets section, below. The command will exit after updating the config file.

-r cfgfile, --load-opts=cfgfile, --no-load-opts

Load options from cfgfile. The no-load-opts form will disable the loading of earlier config/rc/ini files.  --no-load-opts is handled early, out of order.

-v [{v|c|n --version [{v|c|n}]}]

Output version of program and exit.  The default mode is `v', a simple version.  The `c' mode will print copyright information and `n' will print the full copyright notice.

Option Presets

Any option that is not marked as not presettable may be preset by loading values from configuration ("RC" or ".INI") file(s). The file "$HOME/.sharrc" will be used, if present.


See Option Presets for configuration files.

Exit Status

One of the following exit values will be returned:


Successful program execution.


There was an error in command usage.


cannot spawn or write to a shell process


cannot create output file


the working directory structure is invalid


memory allocation failure


invalid input, does not contain a shar file


A specified configuration file could not be loaded.


libopts had an internal operational error.  Please report it to autogen-users@lists.sourceforge.net.  Thank you.

See Also



The shar and unshar programs is the collective work of many authors.  Many people contributed by reporting problems, suggesting various improvements or submitting actual code.  A list of these people is in the THANKS file in the sharutils distribution.


Please put sharutils in the subject line for emailed bug reports.  It helps to spot the message.

Please send bug reports to: bug-gnu-utils@gnu.org


This manual page was AutoGen-erated from the unshar option definitions.

Referenced By

shar(1), tin(1).

30 May 2015 GNU sharutils (4.15.2)