usingcurl/uploads.md: mention --append for FTP and SFTP

Fixes #371

ftp/upload.md

@@ -14,6 +14,11 @@ or to use the local filename as the remote name:
 
     curl -T localfile ftp://ftp.example.com/dir/path/
 
+Append the local file to the target file when uploading instead of
+overwriting, with the `--append` option:
+
+    curl -T uploadthis --append ftp://example.com/directory/remotename
+
 curl also supports [globbing](../cmdline/globbing.md) in the `-T` argument so
 you can opt to easily upload a range of files:
 

index-words

@@ -1,6 +1,7 @@
 %{json}
 --alt-svc
 --anyauth
+--append
 --basic
 --ca-native
 --compressed

usingcurl/uploads.md

@@ -57,11 +57,11 @@ You send off an HTTP upload using the -T option with the file to upload:
 
     curl -T uploadthis http://example.com/
 
-## FTP uploads
+## FTP and SFTP uploads
 
-Working with FTP, you get to see the remote file system you are accessing.
-You tell the server exactly in which directory you want the upload to be
-placed and which filename to use. If you specify the upload URL with a
+Working with FTP and SFTP, you get to see the remote file system you are
+accessing. You tell the server exactly in which directory you want the upload
+to be placed and which filename to use. If you specify the upload URL with a
 trailing slash, curl appends the locally used filename to the URL and then
 that becomes the filename used when stored remotely:
 
@@ -72,6 +72,11 @@ you have used locally, you specify it in the URL:
 
     curl -T uploadthis ftp://example.com/this/directory/remotename
 
+FTP and SFTP also support *appending* to the target file when uploading
+instead of overwriting, with the `--append` option:
+
+    curl -T uploadthis --append ftp://example.com/directory/remotename
+
 Learn much more about FTPing in the [FTP with curl](../ftp/) section.
 
 ## SMTP uploads