I would like to execute the following command ruby do_task.rb && say "done".
The problem is that it say nothing if the command failed. How to fix it so that it would always say something (I don't mind if it say "failed" instead of "done", or just always say "done").
Just replace && with a semicolon ;
ruby do_task.rb;say "done"
Simply :
(ruby do_task.rb && say "done") || (say "fail")
Or as suggested by @LéaGris to avoid spawning subshells,
{ ruby do_task.rb && say "done";}||say "fail"
Or
ruby do_task.rb; say "end"
{ ruby do_task.rb && say "success";}||say "fail". Note the required space after opening and semicolon before closing curly braces.
&& (Boolean arithmetic multiplication ×) has priority over || (Boolean arithmetic addition +), curly braces or parenthesis are not needed for this specific order, test this: false && echo "success" || echo "fail", and true && echo "success" || echo "fail".{ and the semi-colon before the ;}.
... && ... || ...; it is not equivalent to if ...; then ...; else ...; fi, which is what you really want.Another way using a message array (need shell with arrays) indexed with the return code.
message=('success' 'failure')
ruby do_task.rb
say "${message[$?]}"
Also note that if return code of ruby do_task.rb is greater than 1, you will need an array with messages at indexes for each return codes.
To maintain a binary success or failure with the method above:
message=('success' 'failure')
ruby do_task.rb
say "${message[$(($?>0))]}"
say "${message[$((! ! $?))]}", which I would consider more concise, since the ! ! idiom is used in many programming languages for a similar purpose. Of course this is a matter of taste.
command && echo okmeans - print "ok" if command ended with success. If you wish to print something on fail you should use thiscommand || echo failor bothcommand && echo ok || echo failthat'll print "ok" on success or "fail" if something went wrong