On Tue, Feb 13, 2018 at 08:47:56AM -0800, pe...@easthope.ca wrote: > peter@computer:~$ cat wake > #!/bin/bash > input="" > until [[ $input != "" ]] ; do > echo Beginning until loop. > /usr/bin/play /home/peter/ring.wav > read -n 1 -t 4 input > done > > Test the script. > peter@computer:~$ xterm -e ./wake > Yes, it works for bash. Appears [[ or read is not available in dash.
The [[ command is a bashism, yes. The read command is not a bashism, but read -t and read -n *are*. The only portable option for read is -r. Since you're relying heavily on the read-with-timeout, just stick with bash and do not even ATTEMPT it in sh.