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for loop with leading zero in bash 3

Terminal - for loop with leading zero in bash 3
seq -s " " -w 3 20
2009-09-19 21:26:57
User: edo
Functions: seq
5
for loop with leading zero in bash 3

Alternatives

There are 5 alternatives - vote for the best!

Terminal - Alternatives
printf "%02u " {3..20}; echo
2009-09-18 18:48:41
User: Escher
Functions: printf
Tags: bash strings
0

emulates bash4's "echo {03..20}"

Uses bash3 builtin function printf

for i in {0..1}{0..9}; do echo $i; done
2009-09-18 02:51:12
User: dennisw
Functions: echo
Tags: bash strings
-1

Bash 4 will let you do {00..19} to get leading zeros, but Bash 3 doesn't have that feature. This technique gets you partway there (the sequences need be such that the last digit ranges from zero to nine - you can't use this for something like Bash 4's {03..27}, for example). When this limitation is not a problem, you can avoid some complicated string manipulation for concatenating leading zeros.

You can add more digits like this: {0..1}{0..9}{0..9} (ranges from 0 to 99 with up to two leading zeros). To pad with additional zeros:

for i in 000{0..1}{0..9}; do echo $i; done

or

for i in {0..1}{0..9}; do echo "000$i"; done

This is useful for creating values to sort or for creating filenames with a fixed format. Note that this will also work:

touch {0..1}{0..9}

Know a better way?

If you can do better, submit your command here.

What others think

...or in any other shell that lets you execute programs (from gnu coreutils).

Comment by bwoodacre 301 weeks and 3 days ago

In zsh, echo {03..20} also works this way:

echo {03..20}

03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20

Comment by Patola 301 weeks and 2 days ago

Your point of view

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