Linux Tips: quick file copy

Here’s how to make a backup copy of a file:

$ cp MyLongFileName MyLongFileName.bak

Here’s a quicker way of achieving the same thing:

$ cp MyLongFileName{,.bak}

How it works

The shell expands the comma-separated list within the braces, appending each value in turn to the file name. The first character within the braces is a comma, so the first comma-separated string is null; the second is .bak. That means that the second command above expands to be exactly the same as the first.

Want to make a copy of all *.conf files in a directory?

$ for a in *.conf;do cp $a{,.bak};done

What’s your favourite Linux tip?

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