I have a source file that looks like

{
    "admin-user" : {
        "index.md": "Index",
        "user_profil.md": "User Profil"
    }
}

By help of bash and jq I like to concat a string of the second level keys index.md and user_profile.md. Further I like replace .md with .html (key admin-user is unknown an can change)

This is where I hang:

KEYS=$(cat test.json | jq  -r '.[]|keys')

concat_string=""
for i in $KEYS
    do 
        md_name=${i/.md/.html}
        concat_string="$concat_string$md_name"
    done

echo $concat_string

Result:

["index.html","user_profil.html"]

So the result is an array. How can I concat a string with blanks between strings?

CodePudding user response：

All of it can be done from within jq:

map(keys_unsorted[] | sub("\\.md$"; ".html"))

Demo

Alternatively, you can use to_entries to access each .key:

map(to_entries[].key | sub("\\.md$"; ".html"))

Demo

Both will give you an array of strings

["index.html","user_profil.html"]

which you can then -still in jq- concatenate using join and a glue character:

jq -r 'map(keys_unsorted[] | sub("\\.md$"; ".html")) | join(" ")' test.json

Demo

or using the alternative approach:

jq -r 'map(to_entries[].key | sub("\\.md$"; ".html")) | join(" ")' test.json

Demo

Note: Using keys instead of keys_unsorted (as you did in your attempt) will additionally sort the keys.