C++ System Programming Cookbook

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One important aspect of the return status of the commands is that it can be used to (conditionally) run the next command. Two important operators are used for this purpose: && (AND) and || (OR).

In the two commands here, the second is run if—and only if—the first succeeds (the && operator). file.txt is removed if it is copied to the project folder:

cp file.txt ~/projects && rm -f file.txt

Let's have a look at a second example:

cp file.txt ~/projects || echo 'copy failed!'

In the preceding example, the second command is run only if the first fails (the || operator). copy failed! is printed if the copy fails.

In this recipe, we just showed that commands can be combined on a shell script to create a more complex command, and ...