ps -eo ppid= | grep -Fwc $pid

If your grep does not support -w:

ps -eo ppid= | tr -d '[:blank:]' | grep -Fxc $pid

or ps -eo ppid= | awk '$1==ppid {++i} END {print i+0}' ppid=$pid

or (clobbering the positional parameters)

set $(ps -eo ppid=); echo $#

Note that this is not atomic, so the count may be wrong if some processes die and others get spawned in the short span of time it takes to gather the data.

ps -eo ppid= | grep -Fwc $pid

If your grep does not support -w:

ps -eo ppid= | tr -d '[:blank:]' | grep -Fxc $pid

or

ps -eo ppid= | awk '$1==ppid {++i} END {print i+0}' ppid=$pid

or (clobbering the positional parameters)

set $(ps -eo ppid=); echo $#

Note that this is not atomic, so the count may be wrong if some processes die and others get spawned in the short span of time it takes to gather the data.

ps -eo ppid= | grep -Fwc $pid

If your grep does not support -w:

ps -eo ppid= | tr -d '[:blank:]' | grep -Fxc $pid
 
ps -eo ppid= | awk '$1==ppid {++i} END {print i+0}' ppid=$pid

ps -eo ppid= | grep -Fwc $pid

If your grep does not support -w:

ps -eo ppid= | tr -d '[:blank:]' | grep -Fxc $pid

or ps -eo ppid= | awk '$1==ppid {++i} END {print i+0}' ppid=$pid

or (clobbering the positional parameters)

set $(ps -eo ppid=); echo $#

Note that this is not atomic, so the count may be wrong if some processes die and others get spawned in the short span of time it takes to gather the data.