Read JSON data in a shell script

Question

In shell I have a requirement wherein I have to read the JSON response which is in the following format       Messages        Body    172 16 1 42  home 480 1234 5-12-2013 1234 toSort    ReceiptHandle    uUk89DYFzt1VAHtMW2iz0VSiDcGHY H6WtTgcTSgBiFbpFUg5lythf wQdWluzCoBziie8BiS2GFQVoRjQQfOx3R5jUASxDz7SmoCI5bNPJkWqU8ola OYBIYNuCP1fYweKl1BOFUF o2g7xLSIEkrdvLDAhYvHzfPb4QNgOSuN1JGG1GcZehvW3Q 9jq3vjYVIFz3Ho7blCUuWYhGFrpsBn5HWoRYE5VF5Bxc zO6dPT0n4wRAd3hUEqF3WWeTMlWyTJp1KoMyX7Z8IXH4hKURGjdBQ0PwlSDF2cBYkBUA     MD5OfBody    53e90dc3fa8afa3452c671080569642e    MessageId    e93e9238-f9f8-4bf4-bf5b-9a0cae8a0ebc          Here I am only concerned with the  Body  property value  I made some unsuccessful attempts like    jsawk -a  return this Body     or    awk -v k  Body    n split  0 a       for  i 1  i lt  n  i    print a i      But that did not suffice  Can anyone help me with this

User · Accepted Answer

There is jq for parsing json on the command line    jq   Body    Visit this for jq  https   stedolan github io jq

User · Answer

tl dr    cat  tmp so json   underscore select   Messages  Body     172 16 1 42  home 480 1234 5-12-2013 1234 toSort     Javascript CLI tools  You can use Javascript CLI tools like    underscore-cli   json select    CSS-like selectors for JSON    Example  Select all name children of a addons   underscore select   addons  gt   name    The underscore-cli provide others real world examples as well as the json select   doc

User · Answer

Similarly using Bash regexp  Shall be able to snatch any key value pair   key  Body  re      key                    while read -r l  do     if     l     re     then         name    BASH REMATCH 1            value    BASH REMATCH 2            echo   name  value      else         echo  No match      fi done   Regular expression can be tuned to match multiple spaces tabs or newline s   Wouldn t work if value has embedded    This is an illustration  Better to use some  industrial  parser

User · Answer

Here is a crude way to do it   Transform JSON into bash variables to eval them   This only works for    JSON which does not contain nested arrays  and JSON from trustworthy sources  else it may confuse your shell script  perhaps it may even be able to harm your system  You have been warned    Well  yes  it uses PERL to do this job  thanks to CPAN  but is small enough for inclusion directly into a script and hence is quick and easy to debug   json2bash     perl -MJSON -0777 -n -E  sub J   my   p  v        my  r   ref  v  if   r eq  HASH     J    p        v- gt       for keys   v    elsif   r eq  ARRAY      n   0  J   p       n            foreach   v    else    v      s           g     p    s             0-9            1 3   2      p    tr -      p    tr A-Za-z0-9     cd  say   p      v             J  json   decode json            use it like eval    json2bash  lt  lt  lt    a    b   c        Not heavily tested  though   Updates  warnings and more examples see my GIST   Update   Unfortunately  following is a link-only-solution  as the C code is far too long to duplicate here    For all those  who do not like the above solution  there now is a C program json2sh which  hopefully safely  converts JSON into shell variables  In contrast to the perl snippet  it is able to process any JSON  as long as it is well formed   Caveats    json2sh was not tested much  json2sh may create variables  which start with the shellshock pattern        I wrote json2sh to be able to post-process  bson with Shell   bson2json     printf        bsondump   1   echo    END           sed      s        echo          bsons2json     printf      c     for a  do   printf   s  q      c    a     c        bson2json   a   done  echo          bsons2json     bson   json2sh        Explained    bson2json dumps a  bson file such  that the records become a JSON array   If everything works OK  an END0-Marker is applied  else you will see something like END1  The END-Marker is needed  else empty  bson files would not show up   bsons2json dumps a bunch of  bson files as an object  where the output of bson2json is indexed by the filename    This then is postprocessed by json2sh  such that you can use grep source eval etc  what you need  to bring the values into the shell   This way you can quickly process the contents of a MongoDB dump on shell level  without need to import it into MongoDB first

[json] Read JSON data in a shell script

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