How to include environment variable in bash line CURL?
Inside single-quotes, the shell expands nothing. Place them inside double-quotes instead:
curl -u <my-api-token>: \
-X POST https://api.pushbullet.com/v2/pushes \
--header 'Content-Type: application/json' \
--data-binary '{"type": "note", "title": "'"$TR_TORRENT_NAME"'", \
"body": "'"$TR_TORRENT_NAME completed"'."}'
Let's examine how this works by looking at:
$ TR_TORRENT_NAME=MyTorrent
$ echo '{"type": "note", "title": "'"$TR_TORRENT_NAME"'", "body": "'"$TR_TORRENT_NAME completed"'."}'
{"type": "note", "title": "MyTorrent", "body": "MyTorrent completed."}
When the shell variable appears, it is always inside double-quotes. Consequently, it is properly expanded.
Quoting like this is a bit subtle. We have single-quoted strings that contain double-quotes as characters and are next to double-quoted strings. To understand this better, let's take this fragment as a an example:
"'"$TR_TORRENT_NAME"'"
Taking each character in turn:
"
is a literal double-quote character that is inside of a single-quoted string. (For brevity, the beginning of this string is not shown in this fragment.)'
closes a single-quoted string."
opens a double-quoted string.$TR_TORRENT_NAME
is a shell variable that is expanded inside double-quotes."
closes the double-quoted string.'
opens a new single-quoted string."
places a double-quote character inside the single-quoted string.
To include an environment variable in a bash line curl without quotes around the variable content, this worked for me:
--header 'PRIVATE-TOKEN: '"$PRIVATE_TOKEN"''
Or using the scenario that was first described without quotes around the body field:
curl -u <my-api-token>: \
-X POST https://api.pushbullet.com/v2/pushes \
--header 'Content-Type: application/json' \
--data-binary '{"type": "note", "title": "'"$TR_TORRENT_NAME"'", \
"body": '"$TR_TORRENT_NAME completed"'.}'