linux - Bash Script Properties File Using '.' in Variable Name -

i'm new bash scripting , have question using properties .properties file within bash script.

i have seen bash properties file uses'.' between variable names, example:

this.prop.one=someproperty 

and i've seen them called within script like:

echo ${this.prop.one} 

but when try set property error:

./test.sh: line 5: ${this.prop.one}: bad substitution 

i can use properties if without '.' in variable names, , include props file:

#!/bin/bash . test.properties echo ${this_prop_one} 

i able use '.' in variable names, and, if @ possible, not have include . test.properties in script.

is possible?

update:

thanks answers! well, strange. i'm working bash script looks (a service glassfish):

#!/bin/bash  start() {         sudo ${glassfish.home.dir}/bin/asadmin start-domain domain1 }  ... 

...and there property files (build.properties):

# glassfish glassfish.version=2.1 glassfish.home.dir=${app.install.dir}/${glassfish.target} ... 

so, there must way of doing right? these maybe not considered 'variables' definition if they're declared in properties file? again.

load them associative array. require shell bash 4.x, not /bin/sh (which, when symlink bash, runs in posix compatibility mode).

declare -a props while read -r;   [[ $reply = *=* ]] || continue   props[${reply%%=*}]=${reply#*=} done <input-file.properties 

...after can access them so:

echo "${props[this.prop.name]}" 

---

if want recursively references, gets bit more interesting.

getprop__property_re='[$][{]([[:alnum:].]+)[}]' getprop() {   declare -a seen=( ) # prevent endless recursion   declare propname=$1   declare value=${props[$propname]}   while [[ $value =~ $getprop__property_re ]];     nestedprop=${bash_rematch[1]}     if [[ ${seen[$nestedprop]} ]];       echo "error: recursive definition encountered looking $propname" >&2       return 1     fi     value=${value//${bash_rematch[0]}/${props[$nestedprop]}}   done   printf '%s\n' "$value" } 

if have props defined follows (which running loop @ top of answer appropriate input-file.properties):

declare -a props=(   [glassfish.home.dir]='${app.install.dir}/${glassfish.target}'   [app.install.dir]=/install   [glassfish.target]=target ) 

...then behavior follows:

bash4-4.4$ getprop glassfish.home.dir /install/target