One useful command line “pattern” is using find and xargs together. For example, to search for instances of “banana” in a folder hierarchy containing text files, one can do this:

find . -name "*.txt" | xargs grep banana

If the paths contain spaces, this will fail because xargs by default uses spaces as delimiters. For example, a path ./folder1/OS Foo/someFile.txt will yield this error:

grep: ./folder1/OS: No such file or directory
grep: Foo/someFile.txt: No such file or directory

The solution is to use find’s -print0 argument, in conjunction with xarg’s -0  argument:

find . -name "*.txt" -print0 | xargs -0 grep banana

Used like this, find outputs the path with a terminating ASCII NUL character, and xargs uses NUL as a delimiter, so paths with spaces no longer cause problems

Normally, shell scripts can only be executed from the command line. For convenience, especially for users who don’t use Terminal, shell scripts can be made double-clickable in the Finder: simply have the suffix be “.command”, and change the permissions to read/execute.

By default, such scripts execute within the user’s home directory. In some cases, you might want the script to run in its own directory, or some arbitrary directory (such as, say, /tmp). Such a path might contain shell-hostile things like spaces, special characters, etc., and  so this common shell technique will not work:

cd `dirname $0`

The trick is to do this:

#!/bin/sh
cd "$(dirname "$0")"

@AdamBetts asked:

In Yosemite is there no way to set shortcut/mouse button for Today/Notification separately? Seems odd to have no option for that.

Turns out there’s no “proper” way to do this. So, we resort to Apple’s recently revamped Scripting Tools to kludge together a solution that just clicks the UI elements.

With the help of the trusty “Accessibility Inspector.app”, we can work out the following AppleScript methods:

on displayNotificationCenterToday()
	tell application "System Events"
		click menu bar item "Notification Center" of menu bar 2 of process "SystemUIServer"
		click radio button "Today" of radio group 1 of window "NotificationTableWindow" of process "NotificationCenter"
	end tell
end displayNotificationCenterToday
 
on displayNotificationCenterNotifications()
	tell application "System Events"
		click menu bar item "Notification Center" of menu bar 2 of process "SystemUIServer"
		click radio button "Notifications" of radio group 1 of window "NotificationTableWindow" of process "NotificationCenter"
	end tell
end displayNotificationCenterNotifications
 
-- this plus Accessibility Inspector is how I figured out what to click
--tell application "System Events"
--	get properties of every menu bar item of every menu bar of process "SystemUIServer"
-- get properties of menu bar 2 of process "SystemUIServer"
--	click menu bar item "Notification Center" of menu bar 2 of process "SystemUIServer"
--	click radio button "Today" of radio group 1 of window "NotificationTableWindow" of process "NotificationCenter"
--end tell
 
--displayNotificationCenterNotifications()
--displayNotificationCenterToday()

To call these methods from the keyboard, we hook into OSX’s system-wide Services by creating a custom Service in Automator that takes no input from all applications. We can then assign a keyboard shortcut in System Preferences > Keyboard > Shortcuts > Services. The result:

Here’s a package with the two services you need: displayNotificationCenterPanels.zip

Assume you have a variable that’s a C function pointer, and that function may directly or indirectly invoke some GUI code:

typedef void (*MyFunc)(void);
MyFunc func = ...

In a threaded environment, it would be unsafe to execute this function from a background thread. Objective-C’s NSObject has a selector performSelectorOnMainThread  that we can take advantage of, even though our C function isn’t a selector.  Simply create a wrapper object:

@interface TestObject : NSObject {
    MyFunc func;
}
@property MyFunc func;
- (void)invoke;
@end

@implementation TestObject
@synthesize func;
-(void)invoke {
    if (func)
        func();
}
@end

and when you need to execute the C function, create an instance, assign the function pointer, and execute the method that calls it:

TestObject *testObject = [[TestObject alloc] init];
testObject.func = func;
[testObject performSelectorOnMainThread:@selector(invoke)
                             withObject:nil
                          waitUntilDone:YES];

Added bonus: for a much more general solution, see these two blog posts: Invoke any Method on any Thread and Performing any Selector on the Main Thread.