MacOS – OS X : Terminal command to turn ON/OFF SSH server

First off, you can check out a website that lists a lot of these things: http://secrets.blacktree.com/

I, however, just took a brute-force solution:

Copy the Preferences folder

$ cp -r /Library/Preferences before

Launch System Preferences. Make a change via the GUI. Probably best to do one change at a time, e.g. I changed "Display Login Window as:" from "List of users" to "Name and password". Quit System Preferences.

Copy the Preferences folder again:

$ cp -r /Library/Preferences after

See which files changed:

$ diff -ur before after
Binary files before/Preferences/com.apple.loginwindow.plist and after/Preferences/com.apple.loginwindow.plist differ

Compare the two versions. Since they are binary files, you'll need to convert them to XML for comparison. I use an alias for this:

$ alias plist='plutil -convert xml1 -o /dev/stdout'
$ diff -u <(plist before/Preferences/com.apple.loginwindow.plist) <(plist after/Preferences/com.apple.loginwindow.plist)
--- /dev/fd/63  2013-01-23 18:20:29.000000000 +0200
+++ /dev/fd/62  2013-01-23 18:20:29.000000000 +0200
@@ -9,7 +9,7 @@
    <key>RetriesUntilHint</key>
    <integer>3</integer>
    <key>SHOWFULLNAME</key>
-   <false/>
+   <true/>
    <key>lastUser</key>
    <string>loggedIn</string>
    <key>lastUserName</key>

At this point we have located the setting. Confirm we have it with defaults:

$ defaults read /Library/Preferences/com.apple.loginwindow SHOWFULLNAME
1
$ sudo defaults write /Library/Preferences/com.apple.loginwindow SHOWFULLNAME -bool false
$ defaults read /Library/Preferences/com.apple.loginwindow SHOWFULLNAME
0

Launch System Preferences and confirm it changed.

Problem sovled. You can download obfuscated-openssh and compile it in MacOS to get a new ssh command.

Download it from https://github.com/brl/obfuscated-openssh.

Download and install gcc - http://www.mkyong.com/mac/how-to-install-gcc-compiler-on-mac-os-x/

$ sudo ./configure
$ make

If there are some errors while compiling it, remember to check this https://discussions.apple.com/thread/2546848?start=0&tstart=0 (see details below)

$ export LDFLAGS="-L. -Lopenbsd-compat/ -fstack-protector-all -mmacosx-version-min=10.4 -lresolv"
$ ./configure
$ make

All done, you will have a new ssh. Check version.

$ ./ssh -v
OpenSSH_5.2p1, OpenSSL 0.9.8r 8 Feb 2011
usage: ssh [-1246AaCfgKkMNnqsTtVvXxYyz] [-b bind_address] [-c cipher_spec]
           [-D [bind_address:]port] [-e escape_char] [-F configfile]
           [-i identity_file] [-L [bind_address:]port:host:hostport]
           [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]
           [-R [bind_address:]port:host:hostport] [-S ctl_path]
           [-w local_tun[:remote_tun]] [-Z obfuscate_keyword]
           [user@]hostname [command]