Merge branch 'pop-stls'

[nmh] / man / mhfixmsg.man

diff --git a/man/mhfixmsg.man b/man/mhfixmsg.man
index ea342330c9dceccb69a830c2ee71faed425f2212..0a885331b815b54048f1d8274c4ced663ba40052 100644 (file)
--- a/man/mhfixmsg.man
+++ b/man/mhfixmsg.man
@@ -1,21 +1,29 @@
-.TH MHFIXMSG %manext1% "February 8, 2014" "%nmhversion%"
-.\"
+.TH MHFIXMSG %manext1% 2019-03-31 "%nmhversion%"
+.

 .\" %nmhwarning%
 .\" %nmhwarning%

-.\"
+.

 .SH NAME
 .SH NAME

-mhfixmsg \- rewrite MIME messages with various transformations
+mhfixmsg \- nmh's MIME-email rewriter with various transformations

 .SH SYNOPSIS
 .HP 5
 .na
 .B mhfixmsg
 .SH SYNOPSIS
 .HP 5
 .na
 .B mhfixmsg

+.RB [ \-help ]
+.RB [ \-version ]

 .RI [ +folder ]
 .RI [ msgs " | "
 .IR "absolute pathname" " | "
 .RI [ +folder ]
 .RI [ msgs " | "
 .IR "absolute pathname" " | "

-.RB \-file
+.B \-file

 .IR file ]
 .RB [ \-decodetext
 .IR file ]
 .RB [ \-decodetext

-8bit/7bit |
+8bit|7bit|binary |

 .BR \-nodecodetext ]
 .BR \-nodecodetext ]

+.RB [ \-decodetypes
+.IR "type/[subtype][,...]" ]
+.RB [ \-decodeheaderfieldbodies
+utf-8 |
+.BR \-nodecodeheaderfieldbodies ]
+.RB [ \-crlflinebreaks " | " \-nocrlflinebreaks ]

 .RB [ \-textcharset
 .I charset
 .RB "| " \-notextcharset ]
 .RB [ \-textcharset
 .I charset
 .RB "| " \-notextcharset ]


@@ -23,14 +31,16 @@ mhfixmsg \- rewrite MIME messages with various transformations
 .RB [ \-replacetextplain " | " \-noreplacetextplain ]
 .RB [ \-fixboundary " | " \-nofixboundary ]
 .RB [ \-fixcte " | " \-nofixcte ]
 .RB [ \-replacetextplain " | " \-noreplacetextplain ]
 .RB [ \-fixboundary " | " \-nofixboundary ]
 .RB [ \-fixcte " | " \-nofixcte ]

+.RB [ \-checkbase64 " | " \-nocheckbase64 ]
+.RB [ \-fixtype
+.IR mimetype ]

 .RB [ \-outfile
 .IR outfile ]
 .RB [ \-rmmproc
 .IR program ]
 .RB [ \-normmproc ]
 .RB [ \-outfile
 .IR outfile ]
 .RB [ \-rmmproc
 .IR program ]
 .RB [ \-normmproc ]

+.RB [ \-changecur " | " \-nochangecur ]

 .RB [ \-verbose " | " \-noverbose ]
 .RB [ \-verbose " | " \-noverbose ]

-.RB [ \-version ]
-.RB [ \-help ]

 .ad
 .SH DESCRIPTION
 .B mhfixmsg
 .ad
 .SH DESCRIPTION
 .B mhfixmsg


@@ -48,19 +58,24 @@ messages.
 .B mhfixmsg
 passes non-MIME messages through without any transformations.  If no
 transformations apply to a MIME message, the original message or file
 .B mhfixmsg
 passes non-MIME messages through without any transformations.  If no
 transformations apply to a MIME message, the original message or file

-is not modified or removed.
+is not modified or removed.  Thus,
+.B mhfixmsg
+can safely be run multiple times on a message.

 .PP
 The
 .B \-decodetext
 .PP
 The
 .B \-decodetext

-switch enables a transformation to decode each base64 and
-quoted-printable text message part to the selected 8bit or 7bit
-encoding.  If 7bit is selected for a base64 part but it will only fit
-8bit, as defined by RFC 2045, then it will be decoded to 8bit
-quoted-printable.  Otherwise, if the decoded text would not fit the
-selected encoding, the part is not decoded (and a message will be
-displayed if
+switch enables a transformation to decode each base64 and quoted-printable
+text message part to the selected 8-bit, 7-bit, or
+binary encoding.
+If 7-bit is selected for a base64 part but it will only fit
+8-bit, as defined by RFC 2045, then it will be decoded to 8-bit
+quoted-printable.
+Similarly, with 8-bit, if the decoded text would be binary,
+then the part is not decoded (and a message will be displayed if

 .B \-verbose
 .B \-verbose

-is enabled).
+is enabled).  Note that
+.B \-decodetext
+binary can produce messages that are not compliant with RFC 5322, \(sc2.1.1.

 .PP
 When the
 .B \-decodetext
 .PP
 When the
 .B \-decodetext


@@ -69,6 +84,46 @@ linefeed character is removed from text parts encoded in ASCII,
 ISO-8859-x, UTF-8, or Windows-12xx.
 .PP
 The
 ISO-8859-x, UTF-8, or Windows-12xx.
 .PP
 The

+.B \-decodetypes
+switch specifies the message parts, by type and optionally subtype,
+to which
+.B \-decodetext
+applies.  Its argument is a comma-separated list of type/subtype
+elements.  If an element does not contain a subtype, then
+.B \-decodetext
+applies to all subtypes of the type.  The default is
+.B \-decodetypes
+.IR text ;
+it can be overridden, e.g., with
+.B \-decodetypes
+.I text/plain
+to restrict
+.B \-decodetext
+to just text/plain parts.
+.PP
+The
+.B \-decodeheaderfieldbodies
+switch enables decoding of UTF-8 header field bodies, when supplied
+with its mandatory
+.I utf-8
+argument.  The
+.B \-nodecodeheaderfieldbodies
+inhibits this transformation.  The transformation can produce a message
+that does not conform with RFC 2047, \(sc1, paragraph 6, because the decoded
+header field body could contain unencoded non-ASCII characters.  It is
+therefore not enabled by default.
+.PP
+By default, carriage return characters are preserved or inserted at
+the end of each line of text content.  The
+.B \-crlflinebreaks
+switch selects this behavior and is enabled by default.  The
+.B \-nocrlflinebreaks
+switch causes carriage return characters to be stripped from, and not
+inserted in, text content when it is decoded and encoded.  Note that
+its use can cause the generation of MIME messages that do not conform
+with RFC 2046, \(sc4.1.1, paragraph 1.
+.PP
+The

 .B \-textcharset
 switch specifies that all text/plain parts of the message(s)
 should be converted to
 .B \-textcharset
 switch specifies that all text/plain parts of the message(s)
 should be converted to


@@ -76,7 +131,12 @@ should be converted to
 Charset conversions require that
 .B nmh
 be built with
 Charset conversions require that
 .B nmh
 be built with

-.IR iconv (3).
+.IR iconv (3);
+see
+.IR mhparam (1)
+for how determine whether your
+.B nmh
+installation includes that.

 To convert text parts other than text/plain, an external program can
 be used, via the
 .B \-reformat
 To convert text parts other than text/plain, an external program can
 be used, via the
 .B \-reformat


@@ -96,26 +156,37 @@ inserts that text/plain part at the beginning of the containing
 multipart/alternative part, if present.  If not, it creates a
 multipart/alternative part.
 .PP
 multipart/alternative part, if present.  If not, it creates a
 multipart/alternative part.
 .PP

+With the
+.B \-reformat
+switch, multipart/related parts are handled differently than
+multipart/alternative.  If the multipart/related has only a single
+part that is not text/plain and can be converted to text/plain, a
+text/plain part is added and the type of the part is changed to
+multipart/alternative.  If the multipart/related has more than one
+part but does not have a text/plain part,
+.B mhfixmsg
+tries to add one.
+.PP

 The
 .B \-replacetextplain
 switch broadens the applicability of
 The
 .B \-replacetextplain
 switch broadens the applicability of

-.B \-reformat
+.BR \-reformat ,

 by always replacing a corresponding text/plain part, if one exists.
 If
 .B \-verbose
 by always replacing a corresponding text/plain part, if one exists.
 If
 .B \-verbose

-if enabled, the replacement will be shown as two steps:  a removal of
-the text/plain part followed by the usual insertion of a new part.
+is enabled, the replacement will be shown as two steps:  a removal of
+the text/plain part, followed by the usual insertion of a new part.

 .PP
 .B \-reformat
 requires a profile entry for each text part subtype to be reformatted.
 The mhfixmsg-format-text/subtype profile entries are based on external
 .PP
 .B \-reformat
 requires a profile entry for each text part subtype to be reformatted.
 The mhfixmsg-format-text/subtype profile entries are based on external

-conversion programs, and are used the same way that
+conversion programs, and are used in the same way that

 .B mhshow
 uses its mhshow-show-text/subtype entries.  When
 .B nmh
 is installed, it searches for a conversion program for text/html
 content, and if one is found, inserts a mhfixmsg-format-text/html
 .B mhshow
 uses its mhshow-show-text/subtype entries.  When
 .B nmh
 is installed, it searches for a conversion program for text/html
 content, and if one is found, inserts a mhfixmsg-format-text/html

-entry in %etcdir%/mhn.defaults.  An entry of the same name in the
+entry in %nmhetcdir%/mhn.defaults.  An entry of the same name in the

 user's profile takes precedence.  The user can add entries for
 other text subtypes to their profile.
 .PP
 user's profile takes precedence.  The user can add entries for
 other text subtypes to their profile.
 .PP


@@ -134,37 +205,79 @@ programs that parse MIME messages.
 The
 .B \-fixcte
 switch enables a transformation to change the
 The
 .B \-fixcte
 switch enables a transformation to change the

-Content-Transfer-Encoding from an invalid value to 8bit in message
-parts with a Content-Type of multipart, as required by RFC 2045,
-Section 6.4.  That condition is indicated by a \*(lqmust be encoded in
-7bit, 8bit, or binary\*(rq error message from
+Content-Transfer-Encoding from an invalid value to 8-bit in message
+parts with a Content-Type of multipart and message, as required by
+RFC 2045, \(sc6.4.  That condition is indicated by a \*(lqmust be
+encoded in 7bit, 8bit, or binary\*(rq error message from

 .B mhlist
 and other
 .B nmh
 programs that parse MIME messages.
 .PP
 The
 .B mhlist
 and other
 .B nmh
 programs that parse MIME messages.
 .PP
 The

+.B \-checkbase64
+switch enables a check of the encoding validity in base64-encoded
+MIME parts.  The check looks for a non-encoded text footer appended
+to a base64-encoded part.  Per RFC 2045 \(sc6.8, the occurrence of
+a "=" character signifies the end of base-64 encoded content.  If
+none is found, a heuristic is used:  specifically, two consecutive
+invalid base64 characters signify the beginning of a plain text
+footer.  If a text footer is found and this switch is enabled,
+.B mhfixmsg
+separates the base64-encoded and non-encoded content and places
+them in a pair of subparts to a newly constructed multipart/mixed
+part.  That multipart/mixed part replaces the original base64-encoded
+part in the MIME structure of the message.
+.PP
+The
+.B \-fixtype
+switch ensures that each part of the message has the correct MIME type
+shown in its Content-Type header.  It may be repeated.  It is
+typically used to replace \*(lqapplication/octet-stream\*(rq with a
+more descriptive MIME type.  It may not be used for multipart and
+message types.
+.PP
+.B mhfixmsg
+applies two transformations unconditionally.
+The first removes an extraneous trailing semicolon from the parameter
+lists of MIME header field values.
+The second replaces RFC 2047 encoding with RFC 2231 encoding of name
+and filename parameters in Content-Type and Content-Disposition header
+field values, respectively.
+.PP
+The

 .B \-verbose
 switch directs
 .B mhfixmsg
 to output informational message for each transformation applied.
 .PP
 .B \-verbose
 switch directs
 .B mhfixmsg
 to output informational message for each transformation applied.
 .PP

+The return status of
+.B mhfixmsg
+is 0 if all of the requested transformations are performed, or
+non-zero otherwise.
+.RB ( mhfixmsg
+will not decode to binary content with the default
+.B \-decodetext
+setting, but a request to do so is not considered a failure, and is noted
+with
+.BR \-verbose .)
+If a problem is detected with any one of multiple messages such that
+the return status is non-zero, then none of the messages will be
+modified.
+.PP

 The
 .B \-file
 .I file
 switch directs
 .B mhfixmsg
 The
 .B \-file
 .I file
 switch directs
 .B mhfixmsg

-to use the specified
-file as the source message, rather than a message from a folder.
-Only one file argument may be provided.  The
+to use the specified file as the source message, rather than a message
+from a folder.  Only one file argument may be provided.  The

 .B \-file
 switch is implied if
 .I file
 .B \-file
 switch is implied if
 .I file

-is an absolute pathname.
-If the file is \*(lq-\*(rq, then
+is an absolute pathname.  If the file is \*(lq-\*(rq, then

 .B mhfixmsg
 .B mhfixmsg

-accepts the source message on the standard input stream.  If
-the
+accepts the source message on the standard input stream.  If the

 .B \-outfile
 switch is not enabled when using the standard input stream,
 .B mhfixmsg
 .B \-outfile
 switch is not enabled when using the standard input stream,
 .B mhfixmsg


@@ -203,7 +316,7 @@ to add a single transformed message to a different folder, e.g.,
 .RS 5
 mhfixmsg -outfile - | \\
 .RS 0
 .RS 5
 mhfixmsg -outfile - | \\
 .RS 0

-%libdir%/rcvstore +folder
+%nmhlibexecdir%/rcvstore +folder

 .RE
 .RE
 .SS Summary of Applicability
 .RE
 .RE
 .SS Summary of Applicability


@@ -212,18 +325,21 @@ content type and/or encoding as follows:
 .PP
 .RS 5
 .nf
 .PP
 .RS 5
 .nf

-.ta \w'\-fixboundary 'u
-\-decodetext   base64 and quoted-printable encoded text parts
-\-textcharset  text/plain parts
-\-reformat     text parts that are not text/plain
-\-fixboundary  outermost multipart part
-\-fixcte       multipart part
+.ta \w'\-decodeheaderfieldbodies 'u
+\-decodetext              base64 and quoted-printable encoded text parts
+\-decodetypes             limits parts to which -decodetext applies
+\-decodeheaderfieldbodies all message parts
+\-crlflinebreaks          text parts
+\-textcharset             text/plain parts
+\-reformat                text parts that are not text/plain
+\-fixboundary             outermost multipart part
+\-fixcte                  multipart or message part
+\-checkbase64             base64 encoded parts
+\-fixtype                 all except multipart and message parts

 .fi
 .RE
 .fi
 .RE

-.PP

 .SS "Backup of Original Message/File"
 .SS "Backup of Original Message/File"

-If it applies any transformations to a message or file,
-and the
+If it applies any transformations to a message or file, and the

 .B \-outfile
 switch is not used,
 .B mhfixmsg
 .B \-outfile
 switch is not used,
 .B mhfixmsg


@@ -243,7 +359,6 @@ switch disables the use of any
 profile component and negates all prior
 .B \-rmmproc
 switches.
 profile component and negates all prior
 .B \-rmmproc
 switches.

-.PP

 .SS "Integration with inc"
 .B mhfixmsg
 can be used as an add-hook, as described in %docdir%/README-HOOKS.
 .SS "Integration with inc"
 .B mhfixmsg
 can be used as an add-hook, as described in %docdir%/README-HOOKS.


@@ -251,17 +366,24 @@ Note that add-hooks are called from all
 .B nmh
 programs that add a message to a folder, not just
 .BR inc .
 .B nmh
 programs that add a message to a folder, not just
 .BR inc .

-Alternatively, a simple shell alias or function can be used to
-call
+Alternatively, a simple shell alias or function can be used to call

 .B mhfixmsg
 immediately after a successful invocation of
 .BR inc .
 .B mhfixmsg
 immediately after a successful invocation of
 .BR inc .

-For example, with bash:
+One approach could be based on:

 .PP
 .RS 5
 .PP
 .RS 5

-alias inc='inc && mhfixmsg'
+msgs=\`inc -format '%(msg)'\`  &&  [ -n "$msgs" ]  &&  scan $msgs  &&  \
+mhfixmsg -nochangecur $msgs

 .RE
 .PP
 .RE
 .PP

+Another approach would rely on adding a sequence to Unseen-Sequence,
+which
+.B inc
+sets with the newly incorporated messages.  Those could then be
+supplied to
+.BR mhfixmsg .
+An example is shown below.

 .SS "Integration with procmail"
 By way of example, here is an excerpt from a procmailrc file
 that filters messages through
 .SS "Integration with procmail"
 By way of example, here is an excerpt from a procmailrc file
 that filters messages through


@@ -271,11 +393,9 @@ before storing them in the user's
 folder.  It also stores the incoming message in the
 .I Backups
 folder in a filename generated by
 folder.  It also stores the incoming message in the
 .I Backups
 folder in a filename generated by

-.BR mktemp ,
+.BR mkstemp ,

 which is a non-POSIX utility to generate a temporary file.
 which is a non-POSIX utility to generate a temporary file.

-If you do not have that utility, then the
-.BR mkstemp (3)
-function could form the basis for a substitute.  Or,
+Alternatively,

 .B mhfixmsg
 could be called on the message after it is stored.
 .PP
 .B mhfixmsg
 could be called on the message after it is stored.
 .PP


@@ -283,17 +403,121 @@ could be called on the message after it is stored.
 .nf
 .ta \w'\-fixboundary 'u
 PATH = %bindir%:$PATH
 .nf
 .ta \w'\-fixboundary 'u
 PATH = %bindir%:$PATH

-MAILDIR = `mhparam path`
-MKTEMP = 'mktemp Backups/mhfixmsg.XXXXXXXX'
+LANG = en_US.utf8
+MAILDIR = \`mhparam path\`
+#### The Backups directory is relative to MAILDIR.
+MKSTEMP = 'mkstemp -directory Backups -prefix mhfixmsg'

 MHFIXMSG = 'mhfixmsg -noverbose -file - -outfile -'
 MHFIXMSG = 'mhfixmsg -noverbose -file - -outfile -'

-STORE = %libdir%/rcvstore
+STORE = %nmhlibexecdir%/rcvstore

 
 

-:0 w: nmh-worker/procmail.$LOCKEXT
+:0 w: nmh-workers/procmail.$LOCKEXT

 * ^TOnmh-workers@nongnu.org
 * ^TOnmh-workers@nongnu.org

-| tee `$MKTEMP` | $MHFIXMSG | $STORE +nmh-workers
+| tee \`$MKSTEMP\` | $MHFIXMSG | $STORE +nmh-workers
+.fi
+.RE
+.SH "EXAMPLES"
+.SS Basic usage
+To run
+.B mhfixmsg
+on the current message in the current folder, with default transformations to
+fix MIME boundaries and Content-Transfer-Encoding, to decode text and
+application/ics content parts to 8 bit, and to add a corresponding text/plain
+part where lacking:
+.PP
+.RS
+.nf
+mhfixmsg -verbose
+.fi
+.RE
+.SS Specified folder and messages
+To run
+.B mhfixmsg
+on specified messages, without its informational output:
+.PP
+.RS
+.nf
+mhfixmsg +inbox last:4

 .fi
 .RE
 .fi
 .RE

+.SS View without modification
+By default,
+.B mhfixmsg
+transforms the message in place.
+To view the MIME structure that would result from running
+.B mhfixmsg
+on the current message, without modifying the message:
+.PP
+.RS
+.nf
+mhfixmsg -outfile - | mhlist -file -
+.fi
+.RE
+.SS Search message without modification
+To search the current message, which possibly contains base64
+or quoted printable encoded text parts, without modifying it,
+use the
+.B \-outfile
+switch:

 .PP
 .PP

+.RS
+.nf
+mhfixmsg -outfile - | grep \fIpattern\fR
+.fi
+.RE
+.PP
+.B \-outfile
+can be abbreviated in usual MH fashion, e.g., to -o.  The search will be
+on the entire message, not just text parts.
+.SS Translate text/plain parts to UTF-8
+To translate all text/plain parts in the current message to UTF-8, in addition
+to all of the default transformations:
+.PP
+.RS
+.nf
+mhfixmsg -textcharset utf-8
+.fi
+.RE
+.SS Fix all messages in a folder
+To run
+.B mhfixmsg
+on all of the messages in a folder:
+.PP
+.RS
+.nf
+mhfixmsg +folder all
+.fi
+.RE
+.PP
+Alternatively,
+.B mhfixmsg
+can be run on each message separately, e.g., using a Bourne shell loop:
+.PP
+.RS
+.nf
+for msg in \`pick +folder\`; do mhfixmsg +folder $msg; done
+.fi
+.RE
+.PP
+The two appearances of the
+.B +folder
+switch in that command protect against concurrent context changes by other
+.B nmh
+command invocations.
+.SS Run on newly incorporated messages
+To run
+.B mhfixmsg
+on messages as they are incorporated:
+.PP
+.RS
+.nf
+inc  &&  mhfixmsg -nochangecur unseen
+.fi
+.RE
+.PP
+This assumes that the Unseen-Sequence profile entry is set to
+.BR unseen ,
+as shown in
+.IR mh-profile (5).

 .SH FILES
 .B mhfixmsg
 looks for mhn.defaults in multiple locations: absolute pathnames are
 .SH FILES
 .B mhfixmsg
 looks for mhn.defaults in multiple locations: absolute pathnames are


@@ -301,14 +525,14 @@ accessed directly, tilde expansion is done on usernames, and files are
 searched for in the user's
 .I Mail
 directory as specified in their profile.  If not found there, the directory
 searched for in the user's
 .I Mail
 directory as specified in their profile.  If not found there, the directory

-.RI \*(lq %etcdir% \*(rq
+.RI \*(lq %nmhetcdir% \*(rq

 is checked.
 .PP
 .fc ^ ~
 .nf
 is checked.
 .PP
 .fc ^ ~
 .nf

-.ta \w'%etcdir%/mhn.defaults  'u
-^$HOME/\&.mh\(ruprofile~^The user profile
-^%etcdir%/mhn.defaults~^Default mhfixmsg conversion entries
+.ta \w'%nmhetcdir%/mhn.defaults  'u
+^$HOME/.mh_profile~^The user profile
+^%nmhetcdir%/mhn.defaults~^Default mhfixmsg conversion entries

 .fi
 .SH "PROFILE COMPONENTS"
 .fc ^ ~
 .fi
 .SH "PROFILE COMPONENTS"
 .fc ^ ~


@@ -320,13 +544,14 @@ is checked.
 ^rmmproc:~^Program to delete original messages or files
 .fi
 .SH "SEE ALSO"
 ^rmmproc:~^Program to delete original messages or files
 .fi
 .SH "SEE ALSO"

-.IR inc (1),

 .IR iconv (3),
 .IR iconv (3),

+.IR inc (1),
+.IR mh-mkstemp (1),

 .IR mh-profile (5),
 .IR mhbuild (1),
 .IR mhlist (1),
 .IR mh-profile (5),
 .IR mhbuild (1),
 .IR mhlist (1),

+.IR mhparam (1),

 .IR mhshow (1),
 .IR mhshow (1),

-.IR mkstemp (3),

 .IR procmail (1),
 .IR procmailrc (5),
 .IR rcvstore (1),
 .IR procmail (1),
 .IR procmailrc (5),
 .IR rcvstore (1),


@@ -336,17 +561,24 @@ is checked.
 .RB ` +folder "' defaults to the current folder"
 .RB ` msgs "' defaults to cur"
 .RB ` "\-decodetext 8bit"'
 .RB ` +folder "' defaults to the current folder"
 .RB ` msgs "' defaults to cur"
 .RB ` "\-decodetext 8bit"'

+.RB ` "\-decodetypes text,application/ics"'
+.RB ` \-nodecodeheaderfieldbodies '
+.RB ` \-crlflinebreaks '

 .RB ` \-notextcharset '
 .RB ` \-reformat '
 .RB ` \-noreplacetextplain '
 .RB ` \-fixboundary '
 .RB ` \-fixcte '
 .RB ` \-notextcharset '
 .RB ` \-reformat '
 .RB ` \-noreplacetextplain '
 .RB ` \-fixboundary '
 .RB ` \-fixcte '

+.RB ` \-checkbase64 '
+.RB ` \-changecur '

 .RB ` \-noverbose '
 .fi
 .SH CONTEXT
 If a folder is given, it will become the current folder.  The last
 .RB ` \-noverbose '
 .fi
 .SH CONTEXT
 If a folder is given, it will become the current folder.  The last

-message selected from a folder will become the current message.  If
+message selected from a folder will become the current message, unless

 the
 the

+.B \-nochangecur
+switch is enabled.  If the

 .B \-file
 switch or an absolute pathname is used, the context will not be
 modified.
 .B \-file
 switch or an absolute pathname is used, the context will not be
 modified.