Bash / Substring of a string

Question

I try to find a substring of a string.

If I have the string try-30/16, I want to get the 30 string.

so I wrote the next:

n=${"'$b'":'-':'/'}

where $b is a variable I assign before this command. It gives the next:

bad substitution.

How I can do it?

What about awk? $ echo "try-30/16" | awk -F"[-/]" '{print $2}' — fedorqui
– fedorqui, Commented Jun 10, 2013 at 14:53
note that the parameter expansion you are using have this syntax ${parameter:offset:length}. It extracts substring based on index. The parameter expansion part of Bash manual is relevant here. — doubleDown
– doubleDown, Commented Jun 10, 2013 at 15:05

Ziffusion · Accepted Answer · 2013-06-10 14:56:43Z

4

Try this.

b="try-30/16"
n=${b##*-}
n=${n%%/*}
echo $n

answered Jun 10, 2013 at 14:56

Ziffusion

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2 Comments

kojiro Over a year ago

+1. This is a good answer, but could still be improved by pointing to Parameter Expansion documentation.

jaypal singh Over a year ago

Though it wouldn't matter for OP's question, but ## and %% removes the longest match. We can do with just # and % in this particular case.

jaypal singh · Accepted Answer · 2013-06-10 14:57:23Z

2

$ n=${b%/*}
$ n=${n#*-}
$ echo $n
30

answered Jun 10, 2013 at 14:57

jaypal singh

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Comments

anubhava · Accepted Answer · 2013-06-10 15:06:24Z

2

You can also do:

[[ $b =~ [^-]+-([0-9]+) ]] && echo "${BASH_REMATCH[1]}"

OUTPUT:

Live Demo: http://ideone.com/bKHGcS

answered Jun 10, 2013 at 15:06

anubhava

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