ps(1) x -o command= | egrep.1 "^python"
report a snapshot of the current processes
                when used together with the a option.
o format        Specify user-defined format. Identical to -o and --format.

-o format       User-defined format.
                format is a single argument in the form of a blank-separated or comma-separated list,
                which offers a way to specify individual output columns. The recognized keywords are
                described in the STANDARD FORMAT SPECIFIERS section below. Headers may be renamed
                (ps -o pid,ruser=RealUser -o comm=Command) as desired. If all column headers are empty
                (ps -o pid= -o comm=) then the header line will not be output. Column width will increase
                as needed for wide headers; this may be used to widen up columns such as WCHAN
                (ps -o pid,wchan=WIDE-WCHAN-COLUMN -o comm). Explicit width control
                (ps opid,wchan:42,cmd) is offered too. The behavior of ps -o pid=X,comm=Y varies with
                personality; output may be one column named "X,comm=Y" or two columns named "X" and "Y".
                Use multiple -o options when in doubt. Use the PS_FORMAT environment variable to specify
                a default as desired; DefSysV and DefBSD are macros that may be used to choose the
                default UNIX or BSD columns.
    format for a pipeline is:


    redirections specified by the command.



    to specify the format of the time information.

print lines matching a pattern
the matching lines.
source manpages: psegrep