cp times.csv{,.bak} -> makes a copy with *.bak extension. How this works?

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cp times.csv{,.bak} -> makes a copy with *.bak extension. How this works?

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cp times.csv{,.bak} -> makes a copy with *.bak extension. How this works?

Hi

Code:

cp times.csv{,.bak}

makes a copy with *.bak extension. How this works?

Whats the gimmick here? Can't google special characters

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If it works, it's built into your shell, and no gimmickry required(!).

Here's an extract from the bash man page on it:

Code:

Brace Expansion
       Brace expansion is a mechanism by which arbitrary strings may be generated.  This mechanism is similar to pathname expan-
       sion, but the filenames generated need not exist.  Patterns to be brace expanded take the form of an  optional  preamble,
       followed  by either a series of comma-separated strings or a sequence expression between a pair of braces, followed by an
       optional postscript.  The preamble is prefixed to each string contained within the braces, and  the  postscript  is  then
       appended to each resulting string, expanding left to right.

       Brace  expansions  may  be nested.  The results of each expanded string are not sorted; left to right order is preserved.
       For example, a{d,c,b}e expands into `ade ace abe'.

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