Invert results for "for in * do"-loops [duplicate]

Question

Possible Duplicate:
How do I reverse a for loop?

Is there an easy way to invert a for in loop? For a script I want to process files in their reverse order.

So instead of:

for file in *.jpg;
  do echo $file;
done

with the result

001.jpg
002.jpg
003.jpg
...
150.jpg

I want the result

150.jpg
149.jpg
148.jpg
...
001.jpg

Ansgar Esztermann's solution will not work on the 'so called' exact duplicate, but on this example here, with numbers in filenames, which makes it a different thing. I vote to reopen. — user unknown, Feb 7, 2012 at 1:44
@userunknown That's why I didn't merge them, but the duplicate is a more general case. Why would you want a more specific solution? It helps fewer people — Michael Mrozek, Feb 7, 2012 at 2:20
The solutions are more easy. Shorter to type, easier to remember. I have an even shorter one and would gain magnitudes of reputation, if I could publish it! :) — user unknown, Feb 7, 2012 at 3:52

yuyichao · Accepted Answer · 2012-02-06 13:02:52Z

9

You can use

array=(*.jpg)
for ((i = ${#array[@]} - 1;i >= 0;i--)); do
    echo ${array[i]}
done

answered Feb 6, 2012 at 13:02

yuyichao

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Ansgar Esztermann · Accepted Answer · 2012-02-06 13:00:49Z

2

In the given example, you could use

for num in `seq -w 150 -1 1`
  do echo $num.jpg
done

This is, of course, not totally equivalent, as it does not really invert the globbing, but instead generates the sequence externally.

answered Feb 6, 2012 at 13:00

Ansgar Esztermann

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2 Answers 2