Fixed some documentation errors caused by describing the aberrant behaviour of
threads in BSD/OS and mistakenly attributing that to all platforms. Added a couple of paras on how lookups are performed. Documented the difference n how trunctaed responses are handled.
This commit is contained in:
Jim Reid
@@ -13,7 +13,7 @@
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.\" NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
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.\" WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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.\"
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.\" $Id: dig.1,v 1.1 2000/09/03 18:04:24 jim Exp $
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.\" $Id: dig.1,v 1.2 2000/09/08 09:42:56 jim Exp $
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.\"
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.Dd Jun 30, 2000
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.Dt DIG 1
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@@ -57,7 +57,7 @@ Other lookup tools tend to have less functionality than
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.Nm dig .
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.Pp
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Although
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.NM dig
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.Nm dig
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is normally used with command-line arguments, it also has a batch
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mode of operation for reading lookup requests from a file.
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A brief summary of its command-line arguments and options is printed
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@@ -69,15 +69,43 @@ Unlike earlier versions, the BIND9 implementation of
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.Nm dig
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allows multiple lookups to be issued from the command line.
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.Pp
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Unless it is told to query a specific name server,
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.Nm dig
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will read
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.Pa /etc/resolv.conf
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and send queries to the name servers identified by the
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.Nm nameserver
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directives in that file.
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Those name servers are queried in sequence.
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.Nm dig
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dig will send its query to the first name server listed in
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.Pa /etc/resolv.conf .
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If the query times out,
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.Nm dig
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then tries the second name server in the list and if that query
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times out, it will try the third name server.
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When the query to that third name server times out,
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.Nm dig
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repeats the lookups.
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It will try all three servers in sequence again and use a longer timeout
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interval for the second series of lookup attempts.
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If no answer is returned after the the second round of queries, the
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lookup fails.
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.Pp
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The lookup completes when an answer is returned, even if that
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answer indicates an error.
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A commonly held misconception is that the resolver used by tools like
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.Nm dig
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will repeat the query to the next name server listed in
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.Pa /etc/resolv.conf
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if the name server that was queried returns an error reply.
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This is not so.
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.Pp
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When no command line arguments or options are given,
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.Nm dig
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reads
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.Pa /etc/resolv.conf
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and sends a query in parallel
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for details of the root zone \*q.\*q.
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to each of the name servers listed in that file.
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The reply from the name server that responds first is printed
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and any other replies are discarded.
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and makes a lookup for details of the root zone \*q.\*q
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.Sh SIMPLE USAGE
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.Pp
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In normal usage, a typical invocation of
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@@ -103,8 +131,8 @@ argument is provided,
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.Nm dig
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consults
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.Pa /etc/resolv.conf
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and sends parallel queries to each of the name servers listed there.
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The reply from the first name server to respond is displayed.
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and queries the name servers listed there.
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The reply from the name server that responds is displayed.
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.It Ar name
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is the name of the resource record that is to be looked up.
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.It Ar type
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@@ -802,6 +830,18 @@ which returns the eventual answer.
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.Xr RFC1035 ,
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.Xr RFC2535 .
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.Sh BUGS
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Truncated replies are handled differently in the BIND9 implementation
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of
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.Nm dig .
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In previous versions,
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.Nm dig
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would automatically repeat the query using TCP whenever it received
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a truncated response.
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The BIND9 implementation does not do this.
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It will just display the truncated response unless
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.Nm dig
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was told to use a TCP connection when making queries.
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.Pp
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The
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.Fl x
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flag and
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@@ -13,7 +13,7 @@
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.\" NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
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.\" WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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.\"
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.\" $Id: dig.1,v 1.1 2000/09/03 18:04:24 jim Exp $
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.\" $Id: dig.1,v 1.2 2000/09/08 09:42:56 jim Exp $
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.\"
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.Dd Jun 30, 2000
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.Dt DIG 1
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@@ -57,7 +57,7 @@ Other lookup tools tend to have less functionality than
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.Nm dig .
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.Pp
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Although
|
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.NM dig
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.Nm dig
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is normally used with command-line arguments, it also has a batch
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mode of operation for reading lookup requests from a file.
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A brief summary of its command-line arguments and options is printed
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@@ -69,15 +69,43 @@ Unlike earlier versions, the BIND9 implementation of
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.Nm dig
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allows multiple lookups to be issued from the command line.
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.Pp
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Unless it is told to query a specific name server,
|
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.Nm dig
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will read
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.Pa /etc/resolv.conf
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and send queries to the name servers identified by the
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.Nm nameserver
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directives in that file.
|
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Those name servers are queried in sequence.
|
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.Nm dig
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dig will send its query to the first name server listed in
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.Pa /etc/resolv.conf .
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If the query times out,
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.Nm dig
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then tries the second name server in the list and if that query
|
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times out, it will try the third name server.
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When the query to that third name server times out,
|
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.Nm dig
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repeats the lookups.
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It will try all three servers in sequence again and use a longer timeout
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interval for the second series of lookup attempts.
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If no answer is returned after the the second round of queries, the
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lookup fails.
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.Pp
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The lookup completes when an answer is returned, even if that
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answer indicates an error.
|
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A commonly held misconception is that the resolver used by tools like
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.Nm dig
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will repeat the query to the next name server listed in
|
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.Pa /etc/resolv.conf
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if the name server that was queried returns an error reply.
|
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This is not so.
|
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.Pp
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When no command line arguments or options are given,
|
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.Nm dig
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reads
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.Pa /etc/resolv.conf
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and sends a query in parallel
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for details of the root zone \*q.\*q.
|
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to each of the name servers listed in that file.
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The reply from the name server that responds first is printed
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and any other replies are discarded.
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and makes a lookup for details of the root zone \*q.\*q
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.Sh SIMPLE USAGE
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.Pp
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In normal usage, a typical invocation of
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@@ -103,8 +131,8 @@ argument is provided,
|
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.Nm dig
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consults
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.Pa /etc/resolv.conf
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and sends parallel queries to each of the name servers listed there.
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The reply from the first name server to respond is displayed.
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and queries the name servers listed there.
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The reply from the name server that responds is displayed.
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.It Ar name
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is the name of the resource record that is to be looked up.
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.It Ar type
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@@ -802,6 +830,18 @@ which returns the eventual answer.
|
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.Xr RFC1035 ,
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.Xr RFC2535 .
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.Sh BUGS
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Truncated replies are handled differently in the BIND9 implementation
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||||
of
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.Nm dig .
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In previous versions,
|
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.Nm dig
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would automatically repeat the query using TCP whenever it received
|
||||
a truncated response.
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The BIND9 implementation does not do this.
|
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It will just display the truncated response unless
|
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.Nm dig
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was told to use a TCP connection when making queries.
|
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.Pp
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The
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.Fl x
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flag and
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