Watch not showing subshell output

Question

Why does the following not output "hello" line?

watch bash -c 'echo hello'

As this one?

watch 'echo hello'

I expected to have echo write to bash output directly and this to be read by watch and formatted to terminal. Does bash -c not use stdout?

score 5 · Answer 1 · edited Nov 08 '15 at 14:20

5

You have to use double-quotes like this :

watch "bash -c 'echo hello'"

Or, the other way around:

watch 'bash -c "echo hello"'

edited Nov 08 '15 at 14:20

terdon

answered Nov 08 '15 at 14:07

Vinz

But why? Does bash not receive "echo hello" command, but "echo" for example? – sevo Nov 08 '15 at 17:33
Exactly ! You can add `-x` to `bash` to see what it is doing. – Vinz Nov 08 '15 at 19:00

1 Answers1