Unix variable usage

Question

If I have 2 variables with values assigned as below -

a=1; s1=555

Can we print 555 using:

$ echo $s`echo $a`

...? My requirement is use variable 'a' in second variable to print final value of s1.

I have tried it already and failed. Is there any way?

Thanks.

Which shell, *specifically*? There are better answers available for ksh or bash than POSIX sh. — Charles Duffy, Dec 19 '15 at 22:02
...btw, this is the topic of BashFAQ #6: http://mywiki.wooledge.org/BashFAQ/006#Evaluating_indirect.2Freference_variables — Charles Duffy, Dec 19 '15 at 22:03
In Bash, `v="s${a}"; echo ${!v}`. The old way is `eval echo "\$s$a"`, but isn't recommended if you have an alternative (`eval` is dangerous). — Jonathan Leffler, Dec 19 '15 at 22:04

score 0 · Answer 1 · answered Dec 19 '15 at 22:03

0

Bash has native syntax for indirect evaluation support:

a=1
s1=555

varname="s$a"
echo "${!varname}"

answered Dec 19 '15 at 22:03

Charles Duffy

Thank you for your quick response. It worked. :-) – Sumit Burnwal Dec 19 '15 at 22:05

1 Answers1