doc: double-quote use of %f, %p, and %r in literal commands.

Path expansion might expose characters like spaces which would cause
command failure, so double-quote the examples.  While %f doesn't need
quoting since it uses a fixed character set, it is best to be
consistent.

Discussion: https://postgr.es/m/aROPCQCfvKp9Htk4@momjian.us

Backpatch-through: master

doc/src/sgml/backup.sgml

@@ -627,7 +627,7 @@ tar -cf backup.tar /usr/local/pgsql/data
     character in the command.  The simplest useful command is something
     like:
 <programlisting>
-archive_command = 'test ! -f /mnt/server/archivedir/%f &amp;&amp; cp %p /mnt/server/archivedir/%f'  # Unix
+archive_command = 'test ! -f "/mnt/server/archivedir/%f" &amp;&amp; cp "%p" "/mnt/server/archivedir/%f"'  # Unix
 archive_command = 'copy "%p" "C:\\server\\archivedir\\%f"'  # Windows
 </programlisting>
     which will copy archivable WAL segments to the directory
@@ -1294,7 +1294,7 @@ SELECT * FROM pg_backup_stop(wait_for_archive => true);
     character in the command.  The simplest useful command is
     something like:
 <programlisting>
-restore_command = 'cp /mnt/server/archivedir/%f %p'
+restore_command = 'cp "/mnt/server/archivedir/%f" "%p"'
 </programlisting>
     which will copy previously archived WAL segments from the directory
     <filename>/mnt/server/archivedir</filename>.  Of course, you can use something
@@ -1493,11 +1493,11 @@ restore_command = 'cp /mnt/server/archivedir/%f %p'
       If archive storage size is a concern, you can use
       <application>gzip</application> to compress the archive files:
 <programlisting>
-archive_command = 'gzip &lt; %p &gt; /mnt/server/archivedir/%f.gz'
+archive_command = 'gzip &lt; "%p" &gt; "/mnt/server/archivedir/%f.gz"'
 </programlisting>
       You will then need to use <application>gunzip</application> during recovery:
 <programlisting>
-restore_command = 'gunzip &lt; /mnt/server/archivedir/%f.gz &gt; %p'
+restore_command = 'gunzip &lt; "/mnt/server/archivedir/%f.gz" &gt; "%p"'
 </programlisting>
      </para>
     </sect3>

doc/src/sgml/config.sgml

@@ -4059,7 +4059,7 @@ include_dir 'conf.d'
         names that are not present in the archive; it must return nonzero
         when so asked.  Examples:
 <programlisting>
-restore_command = 'cp /mnt/server/archivedir/%f "%p"'
+restore_command = 'cp "/mnt/server/archivedir/%f" "%p"'
 restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"'  # Windows
 </programlisting>
         An exception is that if the command was terminated by a signal (other
@@ -4098,7 +4098,7 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"'  # Windows
         The <xref linkend="pgarchivecleanup"/> module
         is often used in <varname>archive_cleanup_command</varname> for
         single-standby configurations, for example:
-<programlisting>archive_cleanup_command = 'pg_archivecleanup /mnt/server/archivedir %r'</programlisting>
+<programlisting>archive_cleanup_command = 'pg_archivecleanup /mnt/server/archivedir "%r"'</programlisting>
         Note however that if multiple standby servers are restoring from the
         same archive directory, you will need to ensure that you do not delete
         WAL files until they are no longer needed by any of the servers.

doc/src/sgml/high-availability.sgml

@@ -745,8 +745,8 @@ protocol to make nodes agree on a serializable transactional order.
     A simple example of configuration is:
 <programlisting>
 primary_conninfo = 'host=192.168.1.50 port=5432 user=foo password=foopass options=''-c wal_sender_timeout=5000'''
-restore_command = 'cp /path/to/archive/%f %p'
+restore_command = 'cp "/path/to/archive/%f" "%p"'
-archive_cleanup_command = 'pg_archivecleanup /path/to/archive %r'
+archive_cleanup_command = 'pg_archivecleanup /path/to/archive "%r"'
 </programlisting>
    </para>
 

doc/src/sgml/ref/pgarchivecleanup.sgml

@@ -44,7 +44,7 @@ PostgreSQL documentation
    server to use <application>pg_archivecleanup</application>, put this into its
    <filename>postgresql.conf</filename> configuration file:
 <programlisting>
-archive_cleanup_command = 'pg_archivecleanup <replaceable>archivelocation</replaceable> %r'
+archive_cleanup_command = 'pg_archivecleanup <replaceable>archivelocation</replaceable> "%r"'
 </programlisting>
    where <replaceable>archivelocation</replaceable> is the directory from which WAL segment
    files should be removed.
@@ -198,7 +198,7 @@ pg_archivecleanup:  removing file "archive/00000001000000370000000E"
 
   <para>On Linux or Unix systems, you might use:
 <programlisting>
-archive_cleanup_command = 'pg_archivecleanup -d /mnt/standby/archive %r 2>>cleanup.log'
+archive_cleanup_command = 'pg_archivecleanup -d /mnt/standby/archive "%r" 2>>cleanup.log'
 </programlisting>
    where the archive directory is physically located on the standby server,
    so that the <varname>archive_command</varname> is accessing it across NFS,

src/backend/utils/misc/postgresql.conf.sample

@@ -283,7 +283,7 @@
 #archive_command = ''		# command to use to archive a WAL file
 				# placeholders: %p = path of file to archive
 				#               %f = file name only
-				# e.g. 'test ! -f /mnt/server/archivedir/%f && cp %p /mnt/server/archivedir/%f'
+				# e.g. 'test ! -f "/mnt/server/archivedir/%f" && cp "%p" "/mnt/server/archivedir/%f"'
 #archive_timeout = 0		# force a WAL file switch after this
 				# number of seconds; 0 disables
 
@@ -294,7 +294,7 @@
 #restore_command = ''		# command to use to restore an archived WAL file
 				# placeholders: %p = path of file to restore
 				#               %f = file name only
-				# e.g. 'cp /mnt/server/archivedir/%f %p'
+				# e.g. 'cp "/mnt/server/archivedir/%f" "%p"'
 #archive_cleanup_command = ''	# command to execute at every restartpoint
 #recovery_end_command = ''	# command to execute at completion of recovery