Variable from variable [duplicate]

Question

What am I doing wrong here?

A_B_NAME="something"
X=A
Y=B

RESULT=`echo \${X}_\${Y}_NAME`
echo ${RESULT}

and I'm always getting A_B_NAME as a result, but want "something"

Thanks!
Michael

\${X}_\${Y}_NAME is not the variable A_B_NAME, which is $A_B_NAME. — schrodingerscatcuriosity
– schrodingerscatcuriosity, Commented Feb 19, 2020 at 20:13

Stéphane Chazelas · Accepted Answer · 2020-02-19 20:13:06Z

3

You could use eval here (standard):

eval "RESULT=\$${X}_${Y}_NAME"

Or the bash-specific:

varname=${X}_${Y}_NAME
RESULT=${!varname}

And then:

printf '%s\n' "$RESULT"

remember echo can't be used to output arbitrary data, and parameter expansions must be quoted when in list contexts.

answered Feb 19, 2020 at 20:13

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