How do I run a program with a different working directory from current, from Linux shell?

Question

Using a Linux shell, how do I start a program with a different working directory from the current working directory?

For example, I have a binary file helloworld that creates the file hello-world.txt in the current directory.

This file is inside of directory /a.

Currently, I am in the directory /b. I want to start my program running ../a/helloworld and get the hello-world.txt somewhere in a third directory /c.

Answer 1

Call the program like this:

(cd /c; /a/helloworld) 

The parentheses cause a sub-shell to be spawned. This sub-shell then changes its working directory to /c, then executes helloworld from /a. After the program exits, the sub-shell terminates, returning you to your prompt of the parent shell, in the directory you started from.

Error handling: To avoid running the program without having changed the directory, e.g. when having misspelled /c, make the execution of helloworld conditional:

(cd /c && /a/helloworld) 

Reducing memory usage: To avoid having the subshell waste memory while hello world executes, call helloworld via exec:

(cd /c && exec /a/helloworld) 

[Thanks to Josh and Juliano for giving tips on improving this answer!]