${X_${Y}}

[Praveen Bezawada]

Hi
In shell can we do something of the kind

${X_${Y}} to print the value of X_2 when $Y=2

[James R. Ferguson]

Hi Praveen:

While this seems intuitive. I don't think this will work. From the 'sh-posix' man pages in the parameter substitution discussion you can note: "The shell reads all the characters from ${ to the matching } as part of the same word, even if it contains braces or metacharacters."

Regards!

...JRF...

[Satish Y]

No, it is not possible.

Cheers...
Satish.

[James R. Ferguson]

Hi Praveen:

Another comment: You could consider setting and referencing your variables in an array.

...JRF...

[A. Clay Stephenson]

Hi Praveen:

One other option you have is to set up associative arrays in awk so that your values are no referenced by numerical values but rather by strings such as "X1","X2","red","Blue".

Regards, Clay

[Frank Li]

Why not use $X_$Y or $X_${Y} directly ?

The shell will try its best to explain the variable !

[Curtis Larson]

what you need to use is "eval"

eval print \"\$X_$Y\"

sometimes it is easier not to mess with the quotes and do something like

eval z=\$X_$Y
print $z

[Magdi KAMAL]

Hi Praveen,

Try the following , it works :

echo ${X}_${Y}

Magdi

[Carlos Fernandez Riera]

Arrays in shell:

set -A x

x[1]=jjjjjj
x[2]=yyyyyy

y=2

echo ${x[$y]}