learning the Terminal – Part Two



In the last post, we learned how to see all the contents of a folder – invisible and visible files – in the Terminal. However, most of us prefer working in the GUI, so this post is going to show you how to work a bit of Terminal magic to easily turn on and off your invisible files and folders in Finder and the desktop.

Open Terminal, and type or copy/paste the following to the command prompt:

defaults write com.apple.finder AppleShowAllFiles TRUE; killall Finder

(note that all commands in these posts should always be assumed to be case-sensitive).

Press Return.

Now switch out of Terminal and have a look at Finder or your desktop. You should see some ‘hidden’ files now in a sort of greyed-out 50% opacity (files like .DS_Store). If you can’t see such files, go back and check that you typed or copied the entire command correctly.

Assuming you can now see your invisible files in Finder, switch back to Terminal. Press the up arrow key on your keyboard. Notice that the last command you typed reappears.

That’s a handy trick to remember. You can move between your previous commands with the up arrow and down arrow keys to save time re-typing or modifying commands.

In this case, we want to use the last command again, but we also want to modify it. Use the left arrow key to move the cursor back to “True” and then use delete to remove “True”. Leave the cursor where the letter ‘T” was and type FALSE. Make sure the semi-colon ; is still there.

Press Return — you don’t need to move the cursor to the end of the line as you would with a word processor. You can hit Return no matter where the cursor is in the command line and it will execute (or try to) whatever is typed on the whole of the command line.

Now, if you switch back to Finder or the desktop, you should see that all your hidden files have disappeared again.

OK, now that we have tested these commands to check that they work, let’s do something a bit more useful with them.

Switch back to Terminal. Type

^FALSE^TRUE

and press Return.

Wow! Did you see what just happened? You substituted the word “FALSE” from the last command with the word “TRUE” and executed the entire command. In other words, you just made your hidden files visible again! Go and look at the desktop and you’ll see that your invisible files just returned. Try it again. Switch back to Finder and type

^TRUE^FALSE

to replace the word “TRUE” in the last command with the word “FALSE”. Hit Return to execute it.

Using the pattern ^error^correction is a great way to both correct commands you type incorrectly and to run two commands one after the other that have only one term or option different.

Back in Terminal, hit the up arrow to bring the last command back onto the command line. This time, I want you to hit control-A on your keyboard. Notice that this brings the cursor to the start of the command line, which is what we want as we’re going to type in a new command before the “defaults…” part.

With the cursor at the beginning of the line, type

echo

and a space. Then type a double quotation mark right next to the ‘d’ of ‘defaults, so the beginning part looks like this

echo “defaults…

(the ellipsis or ‘…’ is used here just to show that the command continues and should not be in your actual command line)

On the keyboard, press control-E.

This takes the cursor to the end of the command line (remember: control-A to go to the start, control-E to go to the end).

Type another double-quotation mark right after the word ‘Finder’ so the ending looks like this

… ; killall Finder”

Now hit the spacebar once, and type a double right angle-bracket

>>

Hit the spacebar again and type

.bash_profile

The entire command should look like this:

echo “defaults write com.apple.finder AppleShowAllFiles FALSE; killall Finder” >> .bash_profile

Now press Return. Type

^FALSE^TRUE

and press Return one more time.


What did we just do?
To see what you did, type

emacs .bash_profile

As you can see, after testing those two commands on the command line, we’ve now sent them to the .bash_profile file, saving us the job of typing them out again (and possibly making an error when we do so). However, we can’t leave the commands like that – if we do, then they will run every time we log into the Terminal. Rather, we want to use these commands to define functions, just like we did last time with ‘show’ and ‘up’.

To do that, press control-L on the keyboard, then use the down arrow key to bring the cursor to the beginning of the first line with a ‘defaults’ command on it.

Press Return. Press the up arrow once, then type

function hide_all

Press Return and in the new line created type

{

Use the down arrow key to move the cursor down to the line below the “Defaults…FALSE” line and press Return.

In the new line created type

}

Then press Return. Type

function show_all

Press Return and type

{

Use the down arrow key to move the cursor below the “Defaults…TRUE” command. (If you can’t go below the last typed line, then on the keyboard press control-E to move the cursor to the end of the line, the press Return).

Then type

}

Check that the whole thing looks like this:




Once you’re satisfied, hold down the control key while pressing first the x and then c keys. Press y when prompted to confirm the save. You should be returned to the command line. Type

exit

to logout. Then press command-W and command-N to close and reopen Terminal.


What did we do this time?
We just made some new, easy-to-remember commands to show and hide our hidden files in Finder and the desktop. On the way, we learned how to append commands to files using the >> function, as well as how to move the cursor to the beginning and end of a line using ‘control-A’ and ‘control-E’ respectively. We also learned how to recall previous commands on the command line using the arrow keys and how to correct or modify previous commands using the ^error^correction pattern.
Wow, you’ve come a long way in two short tutorials!

To test out what you just did, type

show_all

then press Return.

Switch to Finder and there’s all your hidden files! To make them invisible again, switch back to Terminal and type

hide_all

then Return.

From now on, whenever you want to see your hidden files, just use the show_all command in Terminal. Hide them again with hide_all. :D



SUMMARY
control-A – places the cursor at the beginning of the command line (also works in emacs editor)
control-E – places the cursor at the end of the command line (also works in emacs editor)
control-L – on the command line, this clears the screen (equivalent to the ‘clear’ command); in emacs, this places the caret inside the editor allowing you to edit (=insert point)

up & down keyboard arrows – moves through history of commands

^error^correction – replaces the term after the first ^ with the term given after the second ^ in the previous command, then executes the entire command

echo – sends the following string or command to the specified file (if no file is specified, the string will output back to your terminal screen. In other words, if you type echo hello, the Terminal will print “Hello” on the next line; hence the term ‘echo’! )


Related Posts:

learning the Terminal – Part One
how to change all Desktop backgrounds
Fasttasks – a utility for ten common terminal tasks

About philastokes

Freelance Writer, Developer and Technical Communicator. Explaining the unexplainable with images, video and text. Scripting anything imaginable in Applescript, Bash, C, Objective C, Cocoa, Python and Xcode.

Posted on March 19, 2012, in Developer, OS X Lion, Snow Leopard, Terminal and tagged , , , , , , , , , , , , . Bookmark the permalink. 3 Comments.

  1. hey phila, this is probably very late but i was wondering if you could help me out with something? i worked corners and google’d almost everything i could think of but i cant seem to find a solution.

    in all honesty, i either got lost or made a slight error in doing this, and now everytime i open terminal, my hidden files show, no matter what. i just cant find what command will fix it.

    if you could reply, or email me, itd be greatly appreciated, just trying to fix this.
    thanks.

    • You can’t actually hide files in Terminal. It’s just a question of how you list them. In Terminal,

      $ ls

      will show what you’d see in the Finder. Whereas

      $ ls -a

      will show all files.

      On the other hand, do you mean the Finder always shows your hidden files? If so, then paste this into Terminal to hide them again:

      defaults write com.apple.finder AppleShowAllFiles False; killall Finder

  2. Nice couple of posts. Very useful. Looking forward to more. *hint

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