Normalize spelling

Note that "UNIX" is a trademark, "Unix" is not

src/main/java/org/apache/commons/net/ftp/FTPClient.java

@@ -2251,7 +2251,7 @@ public FTPFile[] listFiles() throws IOException {
      *
      * @param pathname The file or directory to list. Since the server may or may not expand glob expressions, using them here is not recommended and may well
      *                 cause this method to fail. Also, some servers treat a leading '-' as being an option. To avoid this interpretation, use an absolute
-     *                 pathname or prefix the pathname with ./ (unix style servers). Some servers may support "--" as meaning end of options, in which case "--
+     *                 pathname or prefix the pathname with ./ (Unix style servers). Some servers may support "--" as meaning end of options, in which case "--
      *                 -xyz" should work.
      * @return The list of file information contained in the given path in the format determined by the autodetection mechanism
      * @throws FTPConnectionClosedException                                    If the FTP server prematurely closes the connection as a result of the client
@@ -2336,7 +2336,7 @@ public String[] listNames() throws IOException {
      * in the directory is returned. If the pathname corresponds to a file, only that file will be listed. The server may or may not expand glob expressions.
      *
      * @param pathname The file or directory to list. Warning: the server may treat a leading '-' as an option introducer. If so, try using an absolute path, or
-     *                 prefix the path with ./ (unix style servers). Some servers may support "--" as meaning end of options, in which case "-- -xyz" should
+     *                 prefix the path with ./ (Unix style servers). Some servers may support "--" as meaning end of options, in which case "-- -xyz" should
      *                 work.
      * @return The list of file names contained in the given path. null if the list could not be obtained. If there are no file names in the directory, a
      *         zero-length array is returned.

src/main/java/org/apache/commons/net/ftp/parser/EnterpriseUnixFTPEntryParser.java

@@ -69,7 +69,7 @@ public EnterpriseUnixFTPEntryParser() {
     }
 
     /**
-     * Parses a line of a unix FTP server file listing and converts it into a usable format in the form of an {@code FTPFile} instance. If the file
+     * Parses a line of a Unix FTP server file listing and converts it into a usable format in the form of an {@code FTPFile} instance. If the file
      * listing line doesn't describe a file, {@code null} is returned, otherwise a {@code FTPFile} instance representing the files in the
      * directory is returned.
      *

src/main/java/org/apache/commons/net/ftp/parser/MVSFTPEntryParser.java

@@ -159,7 +159,7 @@ public class MVSFTPEntryParser extends ConfigurableFTPFileEntryParserImpl {
      * --------------------------------------------------------------------- Very brief and incomplete description of the zOS/MVS-file system. (Note: "zOS" is
      * the operating system on the mainframe, and is the new name for MVS)
      *
-     * The file system on the mainframe does not have hierarchical structure as for example the unix file system. For a more comprehensive description,
+     * The file system on the mainframe does not have hierarchical structure as for example the Unix file system. For a more comprehensive description,
      * please refer to the IBM manuals
      *
      * @LINK: https://publibfp.boulder.ibm.com/cgi-bin/bookmgr/BOOKS/dgt2d440/CONTENTS
@@ -178,7 +178,7 @@ public class MVSFTPEntryParser extends ConfigurableFTPFileEntryParserImpl {
      *
      * DSORG: PS: sequential, or flat file PO: partitioned dataset PO-E: extended partitioned dataset
      *
-     * The PS file is just a flat file, as you would find it on the unix file system.
+     * The PS file is just a flat file, as you would find it on the Unix file system.
      *
      * The PO and PO-E files, can be compared to a single level directory structure. A PO file consist of a number of dataset members, or files if you will. It
      * is possible to CD into the file, and to retrieve the individual members.
@@ -441,7 +441,7 @@ private FTPFile parseMemberList(final String entry) {
      * <ul>
      *     <li>z/OS-MVS File lists,</li>
      *     <li>z/OS-MVS Member lists,</li>
-     *     <li>unix file lists.</li>
+     *     <li>Unix file lists.</li>
      * </ul>
      * @since 2.0
      */

src/main/java/org/apache/commons/net/ftp/parser/MacOsPeterFTPEntryParser.java

@@ -92,7 +92,7 @@ protected FTPClientConfig getDefaultConfiguration() {
     }
 
     /**
-     * Parses a line of a unix (standard) FTP server file listing and converts it into a usable format in the form of an {@code FTPFile} instance. If the
+     * Parses a line of a Unix (standard) FTP server file listing and converts it into a usable format in the form of an {@code FTPFile} instance. If the
      * file listing line doesn't describe a file, {@code null} is returned, otherwise a {@code FTPFile} instance representing the files in the
      * directory is returned.
      *

src/main/java/org/apache/commons/net/ftp/parser/UnixFTPEntryParser.java

@@ -158,7 +158,7 @@ protected FTPClientConfig getDefaultConfiguration() {
     }
 
     /**
-     * Parses a line of a unix (standard) FTP server file listing and converts it into a usable format in the form of an {@code FTPFile} instance. If the
+     * Parses a line of a Unix (standard) FTP server file listing and converts it into a usable format in the form of an {@code FTPFile} instance. If the
      * file listing line doesn't describe a file, {@code null} is returned, otherwise a {@code FTPFile} instance representing the files in the
      * directory is returned.
      *

src/test/java/org/apache/commons/net/ftp/parser/NTFTPEntryParserTest.java

@@ -234,7 +234,7 @@ public void testParseFieldsOnFile() throws Exception {
         assertEquals("AUTOEXEC.BAK", f.getName());
         assertEquals(5000000000L, f.getSize());
 
-        // test an NT-unix style listing that does NOT have a leading zero
+        // test an NT-Unix style listing that does NOT have a leading zero
         // on the hour.
 
         f = getParser().parseFTPEntry("-rw-rw-r--   1 mqm        mqm          17707 Mar 12  3:33 killmq.sh.log");