CODEWITHSUNDEEP
macososascript
Thomas S.
Thomas S.

Reputation: 6345

Wait until a certain application has exited, then launch another one

On OS X I want to execute an osascript command that waits until a certain application specified by its full .app path has exited, then start another application, e.g. using /usr/bin/open -n /Applications/MyApp.app.

How to achieve the waiting until the application has exited?

Upvotes: 4

Views: 3771

Answers (1)

Paul Guyot
Paul Guyot

Reputation: 6347

A common approach is to perform a waiting loop, for example with pgrep:

while pgrep -f /Applications/TextEdit.app 2>/dev/null ; do sleep 1.0 ; done

Unfortunately, this will sleep too much and delay the start of the other application.

Alternatively, if you know that the application is running, you can use /usr/bin/open:

open -g -W /Applications/TextEdit.app

Unfortunately, this will open the application if it was not running. You could check it is running before calling /usr/bin/open, but this wouldn't be atomic: it could be closing and the open command could restart it.

Both can be encapsulated in osascript (although it probably doesn't make much sense).

osascript -e 'do shell script "while pgrep -f /Applications/TextEdit.app 2>/dev/null ; do sleep 1.0 ; done"'
osascript -e 'do shell script "open -g -W /Applications/TextEdit.app"'

As a side note: open -W actually performs a kqueue wait (non-polling wait) on the process. There might be other commands invoking kqueue and performing the same task without risking restarting the application. It is quite easy to implement in C.

Upvotes: 9

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