Terminal application is located on the following path:

Mac is running on UNIX, which is nearly 40 (yes, forty) years old operating system. One of the major advantages and drawbacks of using UNIX is it's command line.

Everything that you know how to do with mouse and windows (clicking, dragging, etc.) can be done and achieved using the command line.

So what's the big deal?

Power of UNIX is the ability to direct input and output of these relatively simple commands and combine them into infinite structures. A bit like bricks and mortar.

Essentially simple, but put together, the only limit is your imagination.

Here are some examples of guides writen for some of my clients.

To enable Folder X-Ray in QuickLook

• Open Terminal application
• Type defaults write com.apple.finder QLEnableXRayFolders 1
• Type killall Finder

Now try to QuickLook any folder.

By default Finder hides all system and UNIX files from view, but sometimes it is good to see it all

• Open Terminal application
• Type defaults write com.apple.finder AppleShowAllFiles True
• Type killall Finder

All files will now be shown.

Your computer keeps logs of who used it and when

• Open Terminal application
• Type last >~/Desktop/Usage.txt

This will create Usage.txt file on your Desktop with all login dates and times.

Your can also get details on the last session

• Open Terminal application
• Type uptime

This will show you all the details of current login.

By default, Mac OS X doesn't provide an elegant way of logging out idle users.
To make this right, create a Log-out launch agent

• Open TextEdit application
• <?xml version="1.0" encoding="UTF-8"?>
  <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
  <plist version="1.0">
  <dict>
  <key>
  Label</key>
  <string>
  com.username.backgroundUserLogout</string>
  <key>
  ProgramArguments</key>
  <array>
  <string>
  /bin/bash</string>
  <string>
  -c</string>
  <string>
  if [ $(stat -f %u /dev/console) == $UID ]; then if [ -e /tmp/backgroundUserLogout.$UID ]; then rm /tmp/backgroundUserLogout.$UID; fi; elif [ ! -e /tmp/backgroundUserLogout.$UID ]; then touch /tmp/backgroundUserLogout.$UID; elif [ $(( <code>
  date +%s</code>
  - <code>
  stat -f %m /tmp/backgroundUserLogout.$UID || printf 0</code>
  )) -ge $(( 60 * 30 )) ]; then rm /tmp/backgroundUserLogout.$UID; osascript -e 'tell application "System Events" to log out'; fi</string>
  </array>
  <key>
  RunAtLoad</key>
  <true/>
  <key>
  StartInterval</key>
  <integer>
  60</integer>
  </dict>
  </plist>
  

Save file as com.username.backgroundUserLogout.plist in ~/Library/LaunchAgents, log out, and then log back in.

The idle time is defined by 60 * 30, which is 30 minutes.

Get a list of of all TCP/IP traffic your computer is currently making.

• Open Terminal application
• Type netstat -p tcp | grep tcp | awk '{ printf("%s %s", $4, $5)}'

You will get a screen printout of all current network traffic.

Disable writing of status files on the network.

• Open Terminal application
• Type defaults write com.apple.desktopservices DSDontWriteNetworkStores true

This will stop your Mac from writing previews and caches on remote file systems.

Every now and then Spotlight gets corrupt indexes and needs to be updated.

You can get file duplicates by comparing their MD5 checksums. Regardless of how files are named, if their cheksum is the same, they are the same files.

Do not use this on files smaller than 20K in size, because checksums could be identical for different files.

• Open Terminal application
• Type:
  find ~/Folder/Path -size +20 \! -type d -exec md5 -r {} \; | sort | tee /tmp/f.tmp | cut -f 1 -d ' ' | uniq -d | grep -hif - /tmp/f.tmp > ~/dup.txt

You can now examine the contents of dup.txt file on your Desktop, and see where duplicates are...

You can examine exactly what the system reads and writes to disk.

• Open Terminal application
• Type:
  sudo fs_usage -w > ~/Desktop/usage.txt
• Perform activity on your system that you wish to inspect; like checking your email, or saving a document
• After seeing the behaviour you were looking for, switch back to Terminal:
  Hold and press

You can now examine the contents of usage.txt file on your Desktop, and see what the system was doing...

Most software is using XML files to store any application preferences.

XML is very similar to HTML, as it is plain text file, and its structure is based on pairing tags.

Checking the integrity of these tags ensures smooth behaviour of your applications.

• Open Terminal application
• Type sudo plutil ~/Library/Preferences/*.plist
• Type your admin password when prompted

If every file in the list is followed by OK, then everything is fine.
If not, check the offending file name in a text editor.

Before doing remote access, configure your router to pass outside traffic to HOST machine on port 5900.

On HOST machine:

• Apple menu, System Preferences... Sharing, Services
• Tick Remote Login
• Tick Apple Remote Desktop
• In Access privileges... tick VNC viewers may control screen with password.
  Make sure you use a strong 15+ mixed alphanumerical password

On a CLIENT machine download Chicken of the VNC (COTVNC)

• Open Terminal application
• Type ssh -L 5900:127.0.0.1:5900 shortUserNameOnHost@rtr.pub.ip.no
• Press "Return" and type HOST VNC password when prompted.
  This command starts encrypted secure connection between CLIENT and HOST on port 5900.
• Open COTVNC
• Connection menu, New connection command
• Type HOST VNC password...

And there is the HOST screen. You might have to reduce screen resolution and colour depth depending on your upload speed.

To change the Dock in Leopard to 2D appearance

defaults write com.apple.dock no-glass -boolean YES

killall Dock

To lock the contents of the Dock

defaults write com.apple.dock contents-immutable -bool true

killall Dock

To unlock the Dock use:

defaults write com.apple.dock contents-immutable -bool false

killall Dock

To get a more friendly ScreenShare open dialog box

defaults write com.apple.ScreenSharing ShowBonjourBrowser_Debug Yes

To get more options on the toolbar

defaults write com.apple.ScreenSharing 'NSToolbar Configuration ControlToolbar' -dict-add 'TB Item Identifiers' '(Scale,Control,Share,Curtain,Capture,FullScreen,GetClipboard,SendClipboard,Quality)'