Replace some command name 'Tcpdump' with 'tcpdump'

[skip ci]

Author: fxlb

CHANGES

@@ -1796,7 +1796,7 @@ v2.0.1 Sun Jan 26 21:10:10 PDT
 - Ultrix 4.0 is supported (also thanks to Jeff Mogul).
 
 - IBM RT and Stanford Enetfilter support has been added by
-  Rayan Zachariassen <[email protected]>.  Tcpdump has been tested under
+  Rayan Zachariassen <[email protected]>.  tcpdump has been tested under
   both the vanilla Enetfilter interface, and the extended interface
   (#ifdef'd by IBMRTPC) present in the MERIT version of the Enetfilter.
 

CMakeLists.txt

@@ -1397,7 +1397,7 @@ add_custom_target(uninstall
     COMMAND ${CMAKE_COMMAND} -P ${CMAKE_CURRENT_BINARY_DIR}/cmake_uninstall.cmake)
 
 #
-# Tcpdump tests
+# tcpdump tests
 # We try to find the Perl interpreter and, if we do, we have the check
 # rule run tests/TESTrun with it, because just trying to run the TESTrun
 # script as a command won't work on Windows.

CONTRIBUTING.md

@@ -39,7 +39,7 @@ and ask!
 1) Check that there isn't a pull request already opened for the changes you
    intend to make.
 
-2) [Fork](https://help.github.com/articles/fork-a-repo/) the Tcpdump
+2) [Fork](https://help.github.com/articles/fork-a-repo/) the tcpdump
    [repository](https://github.com/the-tcpdump-group/tcpdump).
 
 3) The easiest way to test your changes on multiple operating systems and

README.md

@@ -51,7 +51,7 @@ In the past tcpdump certainly or likely worked on the following platforms:
 * UnixWare
 
 ### Dependency on libpcap
-Tcpdump uses libpcap, a system-independent interface for user-level
+tcpdump uses libpcap, a system-independent interface for user-level
 packet capture.  Before building tcpdump, you must first retrieve and
 build libpcap.
 

tcpdump.c

@@ -997,7 +997,7 @@ tstamp_precision_to_string(int precision)
  * that requires that it be able to do an F_GETFL fcntl() to read
  * the O_ flags.
  *
- * Tcpdump uses ftell() to determine how much data has been written
+ * tcpdump uses ftell() to determine how much data has been written
  * to a file in order to, when used with -C, determine when it's time
  * to rotate capture files.  ftell() therefore needs to do an lseek()
  * to find out the file offset and must, thanks to the aforementioned
@@ -2397,7 +2397,7 @@ DIAG_ON_WARN_UNUSED_RESULT
 	 * devices, and can't just give users that permission,
 	 * you'd make tcpdump set-UID or set-GID).
 	 *
-	 * Tcpdump doesn't necessarily write only to one savefile;
+	 * tcpdump doesn't necessarily write only to one savefile;
 	 * the general only way to allow a -Z instance to write to
 	 * savefiles as the user under whose UID it's run, rather
 	 * than as the user specified with -Z, would thus be to switch