Implement a debug mode ("--debug").

doc/mboxgrep.1

@@ -1,5 +1,4 @@
-.Id $Id: mboxgrep.1,v 1.16 2006-01-18 00:09:58 dspiljar Exp $
-.TH MBOXGREP 1 "26 Jan 2023"
+.TH MBOXGREP 1 "17 Feb 2023"
 .SH NAME
 mboxgrep \- displays email messages matching a pattern
 .SH SYNOPSIS
@@ -86,6 +85,10 @@ Ignore duplicate messages.
 Select input and output mailbox TYPE.  TYPE can be either `mbox' (default), 
 `zmbox' (gzip compressed mbox), `bz2mbox' (bzip2 compressed mbox), `mh', `nnml', 
 `nnmh' or `maildir'.
+.IP "-s, --no-messages"
+Suppress most error messages.
+.IP "--debug"
+Print messages useful for debugging.
 .SH EXAMPLES
 .TP
 \(bu

doc/mboxgrep.info

@@ -169,6 +169,9 @@ options below change such behavior.
 '-s'
      Suppress error messages.
 
+'--debug'
+     Print messages useful for debugging.
+
 
 File: mboxgrep.info,  Node: Search scope selection,  Next: Mailbox type selection,  Prev: Output control,  Up: Invoking
 
@@ -253,11 +256,11 @@ Node: Miscellaneous1827
 Node: File locking2112
 Node: Regexp selection2749
 Node: Output control3301
-Node: Search scope selection4292
-Node: Mailbox type selection4533
-Node: Examples4854
-Node: Bugs5678
-Node: To Vicky6096
+Node: Search scope selection4345
+Node: Mailbox type selection4586
+Node: Examples4907
+Node: Bugs5731
+Node: To Vicky6149
 
 End Tag Table
 

doc/mboxgrep.texi

@@ -6,7 +6,7 @@
 
 @set EDITION 0.7
 @set VERSION 0.7.10
-@set UPDATED 26 Jan 2023
+@set UPDATED 17 Feb 2023
 
 @dircategory Mail
 @direntry
@@ -188,6 +188,9 @@ instance of COMMAND.
 @itemx -s
 Suppress error messages.
 
+@item --debug
+Print messages useful for debugging.
+
 @end table
 
 @node Search scope selection, Mailbox type selection, Output control, Invoking