How to read a properties file which contains keys that have a period character using Shell script

Question

I am trying to read a properties file from a shell script which contains a period     character like below     app properties db uat user saple user db uat passwd secret     bin sh function pause       read -p         file    app properties   if   -f   file    then     echo   file found       file  echo  User Id    db uat user echo  user password     db uat passwd else     echo   file not found   fi   I have tried to parse the file after sourcing the file but it is not working since the keys contains the     character and there are spaces in that value also   My properties file always resides in the same directory of the script or somewhere in  usr share doc

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fork2x  I have tried like this  Please review and update me whether it is right approach or not      bin sh function pause       read -p         file    apptest properties    if   -f   file    then     echo   file found    dbUser  sed       d   file   grep  db uat user     tail -n 1   cut -d     -f2-   sed  s     space       s    space          dbPass  sed       d   file   grep  db uat passwd     tail -n 1   cut -d     -f2-   sed  s     space       s    space           echo database user    dbUser echo database pass    dbPass  else     echo   file not found   fi

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Since variable names in the BASH shell cannot contain a dot or space it is better to use an associative array in BASH like this      bin bash    declare an associative array declare -A arr    read file line by line and populate the array  Field separator is     while IFS     read -r k v  do    arr   k     v  done  lt  app properties   Testing   Use declare -p to show the result      gt  declare -p arr            declare -A arr    db uat passwd   secret   db uat user   saple user

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I found using while IFS     read -r to be a bit slow  I don t know why  maybe someone could briefly explain in a comment or point to a SO answer    I also found  Nicolai answer very neat as a one-liner  but very inefficient as it will scan the entire properties file over and over again for every single call of prop   I found a solution that answers the question  performs well and it is a one-liner  bit verbose line though    The solution does sourcing but massages the contents before sourcing      usr bin env bash  source  lt  grep -v          app properties   grep             awk   split  0 a       print gensub             g   a 1       a 2      echo  db uat user   Explanation   grep -v         discard comment lines grep            discards lines without   split  0 a       splits line at   and stores into array a  i e  a 1  is the key  a 2  is the value gensub             g   a 1    replaces   with   print gensub        a 2   concatenates the result of gensub above with   and value   Edit  As others pointed out  there are some incompatibilities issues  awk  and also it does not validate the contents to see if every line of the property file is actually a kv pair  But the goal here is to show the general idea for a solution that is both fast and clean  Sourcing seems to be the way to go as it loads the properties once that can be used multiple times

User · Answer

I use simple grep inside function in bash script to receive properties from  properties file   This properties file I use in two places - to setup dev environment and as application parameters   I believe that grep may work slow in big loops but it solves my needs when I want to prepare dev environment   Hope  someone will find this useful   Example   File  setup sh     bin bash  ENV   1 -dev   function prop       grep    1   env   ENV  properties cut -d    -f2    docker create       --name myapp-storage       -p   prop  app storage address     prop  app storage port   9000       -h   prop  app storage host         -e STORAGE ACCESS KEY    prop  app storage access-key          -e STORAGE SECRET KEY    prop  app storage secret-key          -e STORAGE BUCKET    prop  app storage bucket          -v    prop  app data-path   storage   app storage       myapp-storage latest  docker create       --name myapp-database       -p    prop  app database address       prop  app database port    5432       -h    prop  app database host          -e POSTGRES USER    prop  app database user          -e POSTGRES PASSWORD    prop  app database pass          -e POSTGRES DB    prop  app database main          -e PGDATA   app database        -v    prop  app data-path   database   app database       postgres 9 5   File  env dev properties  app data-path  apps myapp                                                                 Server properties                                                             app server address 127 0 0 70 app server host dev myapp com app server port 8080                                                                Backend properties                                                             app backend address 127 0 0 70 app backend host dev myapp com app backend port 8081 app backend maximum threads 5                                                                Database properties                                                             app database address 127 0 0 70 app database host database myapp com app database port 5432 app database user dev-user-name app database pass dev-password app database main dev-database                                                                Storage properties                                                             app storage address 127 0 0 70 app storage host storage myapp com app storage port 4569 app storage endpoint http   storage myapp com 4569 app storage access-key dev-access-key app storage secret-key dev-secret-key app storage region us-east-1 app storage bucket dev-bucket   Usage     setup sh dev

User · Answer

As  Bourne  shell variables cannot contain dots you can replace them by underscores  Read every line  translate   in the key to   and evaluate     bin sh  file    app properties   if   -f   file    then   echo   file found      while IFS     read -r key value   do     key   echo  key   tr              eval   key     value    done  lt    file     echo  User Id             db uat user    echo  user password       db uat passwd  else   echo   file not found   fi   Note that the above only translates   to    if you have a more complex format you may want to use additional translations  I recently had to parse a full Ant properties file with lots of nasty characters  and there I had to use   key   echo  key   tr  -      tr -cd  A-Za-z0-9

[linux] How to read a .properties file which contains keys that have a period character using Shell script

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