WonderGen ~ # 0 tac services|sed -ne ‘/^[^#].*file.*\s.*\/udp.*/{N;/\(^[^#]*\s.*\)\/udp\(.*\)#*.*\n\1\/tcp\2/!{s/\n.*//p}}’|wc -l
0
WonderGen ~ # 0 tac services|sed -ne ‘/^[^#].*file.*\s.*\/udp.*/{N;/\(^[^#]*\s.*\)\/udp\(.*\)#*.*\n\1\/tcp\2/!{s/\n.*//p}}’
WonderGen ~ # 0
# there are no services which are not commented, containing file in their name and running only in udp

WonderGen ~ # 0 tac services|sed -ne ‘/^[^#]*\s.*\/udp.*/{N;/\(^[^#]*\s.*\)\/udp\(.*\)#*.*\n\1\/tcp\2/!{s/\n.*//p}}’
mandelspawn 9359/udp mandelbrot # network mandelbrot
router 520/udp route routed # local routing process
syslog 514/udp

who 513/udp whod # who’s logged in to machines
comsat 512/udp biff # notify users of new mail received
igmpv3lite 465/udp smtps ssmtp # IGMP over UDP for SSM
test2 37/udp timserver
test 18/udp
WonderGen ~ # 0 tac services|sed -ne ‘/^[^#]*\s.*\/udp.*/{N;/\(^[^#]*\s.*\)\/udp\(.*\)#*.*\n\1\/tcp\2/!{s/\n.*//p}}’|wc -l
8
WonderGen ~ # 0
# there are 8 services running only in udp

########################################################################
# Explanations
#
# tac services|sed -ne ‘/^[^#]*\s.*\/udp.*/{N;/\(^[^#]*\s.*\)\/udp\(.*\)#*.*\n\1\/tcp\2/!{s/\n.*//p}}’|wc -l
#
# this will count/print all services which are running only in udp. We asume that the services file have the following structure:
# tcpmux 1/tcp # TCP port service multiplexer
# tcpmux 1/udp
# compressnet 2/tcp # Management Utility
# compressnet 2/udp
#
# – if one service can run in tcp and udp, the udp record will be on 2nd line
#
# tac – reversed cat
# tac services|sed -ne ‘/^[^#] – search for lines which don’t start with #
# tac services|sed -ne ‘/^[^#]*\s.* – search for lines which don’t start with # and have(or not) some chars followed by
# space char and have(or not) something after it
# tac services|sed -ne ‘/^[^#]*\s.*\/udp.* – search for lines which don’t start with # and have(or not) some chars
# followed by space char and have(or not) something after it then /udp followed(or not) by something
# tac services|sed -ne ‘/^[^#]*\s.*\/udp.*/{ – start executing commands
#
# The idea is to match 2 concecutive lines, actually to find couples
# which don’t match
#
# tac services|sed -ne ‘/^[^#]*\s.*\/udp.*/{N; – add the next line to the current one and they will be used as
# single one for test, the two lines are separated by \n
# tac services|sed -ne ‘/^[^#]*\s.*\/udp.*/{N;/\(^[^#]*\s.*\)\/udp – the same as the previous one but in the new
# concatenated line we want to save the part before /udp for later use
# tac services|sed -ne ‘/^[^#]*\s.*\/udp.*/{N;/\(^[^#]*\s.*\)\/udp\(.*\)#*.*\n – in the first part(up to the \n) of the new
# concatenated line save the parts before /udp and after /udp up to
# ‘#'(may exist or not) and may be followed or not by chars
#
# this is to avoid lines like
# qrh 752/udp passwd_server # Kerberos passwd server
# qrh 752/tcp passwd_server
# which are different not only by /tcp /udp but also by the comment
#
# tac services|sed -ne ‘/^[^#]*\s.*\/udp.*/{N;/\(^[^#]*\s.*\)\/udp\(.*\)#*.*\n\1\/tcp\2/ – in the new concatenated line
# compare the parts before and after /udp in the first part (up to the \n)
# with the parts before and after /tcp in the second part
#
# tac services|sed -ne ‘/^[^#]*\s.*\/udp.*/{N;/\(^[^#]*\s.*\)\/udp\(.*\)#*.*\n\1\/tcp\2/! – VERY IMPORTANT – reverse the
# selection
#
# tac services|sed -ne ‘/^[^#]*\s.*\/udp.*/{N;/\(^[^#]*\s.*\)\/udp\(.*\)#*.*\n\1\/tcp\2/!{ – start executing commands
# on the new concatenated line
#
# tac services|sed -ne ‘/^[^#]*\s.*\/udp.*/{N;/\(^[^#]*\s.*\)\/udp\(.*\)#*.*\n\1\/tcp\2/!{s/\n.*//p}} – on the concatenated
# line replace \n and everything after it with nothing and print it
#