Bash and zsh both have a very neat feature for expanding a single word into more: brace expansion.
For the simplest example, imagine you need to move file.old as file.new. Normally you type:
$ mv file.old file.newBrace expansion can save you a little bit of typing:
$ mv file.{old,new}
The command actually executed will be identical to the previous one, “file.{old,new}” gets converted into “file.old file.new”.
You can also provide a number range inside the brace:
% echo test{1..13} test1 test2 test3 test4 test5 test6 test7 test8 test9 test10 test11 test12 test13
With a third parameter, the number will be increased by that much each time (step):
% echo test{1..13..2} test1 test3 test5 test7 test9 test11 test13
Only a zsh feature is padding. You can add leading zeros to generated number to make them all the same (character) size, by adding zero(s) to the third parameter:
% echo test{1..100..010} test001 test011 test021 test031 test041 test051 test061 test071 test081 test091
Zsh offers even more flexibility after setting BRACE_CCL option – you can use range of characters as well:
% setopt BRACE_CCL % echo test{a-d} testa testb testc testd
Hi Tomek!
Braces are sweet. You can also leave the first brace argument out if you just want to append something to the filename. I find myself doing this sometimes when making a quick and dirty backup of a file:
cp foo.txt{,~}.I had no idea you could specify an interval for a number range. That’s cool
Are you using zsh a lot these days? noting a few blog entries… worth a look?
Absolutely worth a look – I use zsh on daily basis for a while now, couldn’t go back to bash
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haha. now there’s an endorsement! I’ll have to take a looks so
what are the main reasons? sounds like a good opportunity for a blog post 