Question : Adding value to be part of file name

I have a text file say yrmnth.txt that contains value 201001 .
 
I'm able to echo the value from the txt File using the below command in solaris
 
var=`cat /appl/oas/apps/amrl/mnthend/yrmnth.txt`
echo $var                                   -- Displays 201001
 
Now i want this value to be part of my file name
as     RL_201001_RLMTR01.LIS
 
 i tried both RL_$var_RLMTR01.LIS  as well as RL_`$var`_RLMTR01.LIS and ws unable to get the desired output.
 
Calling the Below command in shell script  [where $ variables are enviroment variables  where paths are defined in another shell script]  
$oradev_bin/rwclient.sh server=$oracle_repsrv module=$source_path/RLVHR46A.RDF userid=$oradev_user p_repid='RLVHR46A' p_compcd=4  p1=1 destype=file desformat=WIDE   desname=$spool_path/RL_$var_RLVHR46A.LIS  CMDFILE=$source_path/ACYM.CMD
 
Thanking You

Answer : Adding value to be part of file name

You need to use braces around the variable to disambiguate it, ie:

desname=$spool_path/RL_${var}_RLVHR46A.LIS