On Apr 14, 2017 08:41, "Edmond Yuen" wrote: Please verify the script below: #/bin/bash D=`date +%Y%m%d` i="someparameter" echo $D_$i echo $D\_$i echo $D echo $i echo _ // my system is debian with coreutils 8.26-3 // // db=`date -d "-1day" +%Y%m%d` // i="0" This is the result from my system ~$ echo "$db_$i" 0 ~$ echo "$db\_$i" 20170413\_0 ~$ echo "$db$i" 201704130 This output looks ok to me. Do you expect something different? and why?