get files from directory in bash and build JSON object using jq-CodePudding

I am trying to build list of JSON objects with the files in a particular directory. I am looping thru the files and creating the expected output object as string. I am sure there is a better way of doing this using jq.

Can someone please help me out here?

# input
files=($( ls * )) 
prefix="myawesomeprefix"
# expected output

{
  "listoffiles": [
    {"file":"myawesomeprefix/file1.txt"},
    {"file":"myawesomeprefix/file2.txt"},
    {"file":"myawesomeprefix/file3.txt"},
 ]
}

CodePudding user response：

You shouldn't parse the output of ls. If installed, you could use tree with the -J option to produce a JSON listing, which you can transform to your needs using jq:

tree -aJL 1 | jq '
  {listoffiles: first.contents | map({file: ("myawesomeprefix/"   .name)})}
'

Or more comfortably using --arg:

tree -aJL 1 | jq --arg prefix myawesomeprefix '
  {listoffiles: first.contents | map({file: "\($prefix)/\(.name)"})}
'

CodePudding user response：

This is another alternative :

jq -n --arg prefix "myawesomeprefix"\
    '.listoffiles = ($ARGS.positional |
                     map({file:($prefix "/" .)}))'\
    --args *

CodePudding user response：

You can try the nice little command line tool jc:

ls -l | jc --ls

It converts the output of many shell commands to JSON. For reference have a look there in Github https://github.com/kellyjonbrazil/jc .

Then you can transform the result using jq.

CodePudding user response：

If you don't have any "problematic" file names, e.g. ones that have new lines as part of their name, the following should work:

ls -1 | jq -Rn '{ listoffiles: [inputs | { file: "prefix/\(.)" }] }'

It reads each line as string, and reads them through the inputs filter (must be combined with -n null-input). It then builds your object.

$ cat <<LS | jq -Rn '{ listoffiles: [inputs | {file:"prefix/\(.)"}] }'
file1
file2
file with spaces
LS
{
  "listoffiles": [
    {
      "file": "prefix/file1"
    },
    {
      "file": "prefix/file2"
    },
    {
      "file": "prefix/file with spaces"
    }
  ]
}

You could use for with a glob which should handle new lines in file names as well. But it requires you to chain 2 jq commands:

for f in *; do
  printf '%s' "$f" | jq -Rs '{file:"prefix/\(.)"}';
done | jq -s '{listoffiles:.}'

To specify the prefix as variable from the outside, use --var, e.g.

jq --var prefix "yourprefixvalue" '$prefix   .'