How to have a command with lots of quotes running remotely?

Question

I am trying to run a command-line remotely that contains some single, double quotes.

1) This is the command I want to have it running on remote host.

  echo '{"id":12345,"name":"activate_cluster"}' 

which should be of the exactly same format. Not any missing characters.

2) This is the full command I have used to trigger this command from my local host:

expect bashscript $hostname $user $pwd 'echo \'\{\"id\":12345\,\"name\":\"activate_cluster\"\}\'

3) But when it reaches the remote host, this command becomes,

echo {"id":12345,"name":"activate_cluster"}

The pair of single quotes is gone! Is there a way I can fix this?

Answer 1

You cannot embed a single quote within single quotes in bash: https://www.gnu.org/software/bash/manual/bashref.html#Single-Quotes

You'll have to do something like this:

expect bashscript $hostname $user $pwd 'echo '\''{"id":12345,"name":"activate_cluster"}'\'
# ...........................................^^^^......................................^^^

'\\'' -- the first quote ends the opening quote from 'echo , the escaped quote appends a literal quote, and the third one opens a new quoted string. Within single quotes, you don't need to go nuts with backslashes -- they're all literal characters in there.

Another approach would be to store the command in a separate variable:

cmd=$(cat <<'END'
echo '{"id":12345,"name":"activate_cluster"}' 
END
)
expect bashscript $hostname $user $pwd "$cmd"

A little wordier but much tidier, no?