I was using printf to format a number in bash:
$ printf -- ">>%4d\n" 1
>> 1
This works fine, but when i do the same thing in a subshell:
$ echo $(printf -- ">>%4d\n" 1)
>> 1
Why are the spaces removed? I have absolutely no idea.
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Charles Duffy
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Sam De Meyer
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3 Answers
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The sub-shell isn't doing it. Not directly.
The issue here is that you aren't quoting the sub-shell result. As such the shell is word-splitting the resulting text (which drops extraneous spaces) and then hands a list of words to echo which happily spits them back out at you (without the extra spaces).
This is essentially no different than running echo 1 and wondering where the extra spaces went.
My answer here discusses this a bit as well.
Community
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Etan Reisner
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Thx, i did echo "$(printf -- ">>%4d\n" 1)", and it works as expected now. Thanks for your quick and clear answer. I will mark the question as solved – Sam De Meyer Sep 08 '14 at 20:00
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Make sure to use quotes while using command substitution to get spacing right:
echo "$(printf -- ">>%4d\n" 1)"
>> 1
anubhava
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Below is the link which gives a detailed description when and why one should quote in their scripts, take a look it will be useful.
Ram
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