How to get the char at a given position of a string in shell script?

Question

How to get the char at a given position of a string in shell script?

Answer 1

In bash with "Parameter Expansion" ${parameter:offset:length}

$ var=abcdef
$ echo ${var:0:1}
a
$ echo ${var:3:1}
d

Edit: Without parameter expansion (not very elegant, but that's what came to me first)

$ charpos() { pos=$1;shift; echo "$@"|sed 's/^.\{'$pos'\}\(.\).*$/\1/';}
$ charpos 8 what ever here
r

Answer 2

Alternative to parameter expansion is expr substr

substr STRING POS LENGTH
    substring of STRING, POS counted from 1

For example:

$ expr substr hello 2 1
e