Provided by: guncat_2.01.00-1build1_amd64 
NAME
guncat - catenates files, unencrypting pgp encrypted sections
SYNOPSIS
guncat [OPTIONS] [file(s)]
[OPTIONS] - cf. section OPTIONS
[file(s)] - optional files to process (cf. section INPUT FILE(S))
DESCRIPTION
Guncat was designed to tackle a problem encountered with (partially) PGP encrypted files (which may exist
in, e.g., mailboxes). Tools to process text-files (like grep(1), or less(1)) may be used to process those
files, but those tools leave PGP encrypted sections inside such files as-is. As a consequence, browsing
the `real’ contents (i.e., clear-text sections and the unencrypted content of PGP encrypted sections) of
those files is difficult.
Guncat acts comparably to cat, but unencrypts encrypted sections encountered in the files processed by
guncat, copying the unencrypted information to guncat’s standard output stream, which may thereupon be
processed by other tools.
PGP/GPG encrypted sections are surrounded by the following markers:
-----BEGIN PGP MESSAGE-----
and
-----END PGP MESSAGE-----
When guncat encounters such sections they are processed by gpg(1). Gpg needs a passphrase to unencrypt
such sections. If not already available (from gpg-agent(1)) the required passphrase is requested by
guncat, whereafter it is used by gpg.
When an incorrect passphrase is entered two additional attempts to provide the correct passphrase are
allowed. If the third attempt also fails, guncat terminates. While processing files guncat may have to
reposition their current file pointer locations. If repositioning is not supported guncat terminated with
an error message.
RETURN VALUE
Guncat returns 0 to the operating system unless an error occurs (0 is also returned when information
providing option (like --version or --gpg-command) are specified). 1 is returned if gpg could not decrypt
an encrypted section or when called without options or s to process.
INPUT FILE(S)
When no file arguments are provided input may be provided using standard input stream redirection.
When option --passphrase is specified the content of the first line of a specified file is used as the
passphrase (see option --passphrase below.
Any other argument is considered a filename (path specifications are allowed) specifying a file to be
processed (in sequence) by guncat.
If a file cannot be read or decrypted guncat terminates with an error message.
OPTIONS
In the following overview of options single letter options, when available, are listed between
parentheses following their associated long-option alternatives. Single letter options require arguments
if their long option alternatives require arguments as well.
o --dots (-d)
A dot (.)is written to the standard error stream after processing each block of 8192 input lines.
This option is ignored when the --pgp-ranges, --section-lines or --verbose options are specified.
o --gpg-command
Show the gpg command that would be used, and quit, returning 0.
o --gpg-messages=path (-m)
Path to the file receiving the messages written by the GPG program to its standard error stream.
Use `stdout’ to write the messages to the standard output stream, use `stderr’ to write the
messages to the standard error stream. If not specified the messages written by the GPG program
are not shown.
o --gpg-option=option
Add option to gpg’s call. If the option contains blanks, surround option by single or double
quotes. Option gpg-option may repeatedly be specified.
o --gpg-path=path
Path to the gpg program (default: /usr/bin/gpg)
o --help (-h)
Basic usage information is written to the standard output stream.
o --no-errors
When this options is specified guncat terminates gpg returns a non-zero exit value.
o --passphrase=path
By default guncat obtains the passphrase to use by prompting the user to enter the passphrase. The
passphrase may also be read from a separate file whose path is specified as argument to the
--passphrase option. When the --passphrase option is specified and the provided password is
incorrect, guncat terminates.
o --pgp-ranges (-r)
the lines-ranges of complete PGP MESSAGE sections are reported. No additional output is produced.
o --quoted-printable (-q)
merely decrypt PGP messages, keeping their quoted-printable content (by default quoted-printable
content like ’=3D’ is converted to ascii).
o --reduce-headers (-R)
When encountering mail headers (starting at lines beginning with `From ’ and ending at the next
empty line) only output the mail headers Cc:, Date:, From:, Subject:, and To:.
o --section-lines (-S)
In the output precede decrypted PGP MESSAGE sections by their line numbers, using a format like
****************************
filename:43:104: PGP MESSAGE
****************************
where the first number refers to the first line number of the PGP section and the second number
refers to last line number of the PGP section
o --skip-incomplete (-s)
Incomple PGP MESSAGE sections are ignored and are not outputted. By default the program’s output
also contain the lines of any incomplete PGP MESSAGE sections that were encountered.
o --time-limit=seconds (-T)
Option --time-limit is used to specify the max. time in seconds that gpg is allowed to run while
decrypting a single encrypted section. By default no time limit is used. This option is useful
when the file to process might contain errors in encrypted sections (like a missing END PGP
MESSAGE line).
o --tty-OK (-t)
Option --no-tty is not specified when calling gpg. By default it is specified.
o --verbose=path (-V)
Path to where guncat should write additional messages. Specify - to write the messages to the
standard error stream.
o --version ((-v))
Guncat’s version number is written to the standard output stream, terminating guncat, returning
exit value 0.
SEE ALSO
gpg(1), gpg-agent(1), grep(1), less(1).
BUGS
None reported
COPYRIGHT
This is free software, distributed under the terms of the `GNU General Public License’. Guncat is
available at https://fbb-git.gitlab.io/guncat/
AUTHOR
Frank B. Brokken (f.b.brokken@rug.nl).
guncat_2.01.00 2014-2022 guncat(1)