On most running servers, the command:
asterisk -rx 'core show channels verbose' | cut -c1-15 | grep 'pstn_' | wc -l
always returns 0.
This is because very much depends on the specific configuration asterisk.
For example, in my original output (asterisk -rx 'core show channels verbose) there is no correspondence to the string 'pstn_'.
On most running servers, the command:
asterisk -rx 'core show channels verbose' | cut -c1-15 | grep 'pstn_' | wc -lalways returns 0. This is because very much depends on the specific configuration asterisk. For example, in my original output (asterisk -rx 'core show channels verbose) there is no correspondence to the string 'pstn_'.