strange behaviour sys.argv

[schnupfy]

On Apr 17, 3:00 pm, Charles Sanders <C.delete_this.Sand... at BoM.GOv.AU>
wrote:
> Michael Hoffman wrote:
> > schnupfy wrote:
>
> >> I am not used to python and I am wondering about this thing:
>
> > This is not a Python question. It is a question about how to use bash.
>
> [snip]
>
> Michael is correct, it is a bash thing, nothing to do with python.
> bash (and other *nix like shells) generally break arguments on
> white space. Quoting (both single and double) overrides this with
> (slightly) different rules for different shells.
>
>  > /root/mk/services.py 192.168.1.101 critical "192.168.1.101
>  > 192.168.1.101 SNMPv2-MIB::sysUpTime.0 14:13:02:57.06 SNMPv2-
>  > MIB::snmpTrapOID.0 SNMPv2-SMI::enterprises.789.0.13 SNMPv2-
>  > SMI::enterprises.789.0.2"cfCannotTakeover == 1 priority == critical"
>  > SNMP-COMMUNITY-MIB::snmpTrapAddress.0 192.168.1.101 SNMP-COMMUNITY-
>  > MIB::snmpTrapCommunity.0 "public""
>
>         Assuming this has been folded and actually is one long
> line (which the output confirms), you have passed the python
> script seven arguments
>
>         '192.168.1.101'  (blank seperated)
>         'critical'       (also blank seperated)
> a string extending from just after the first double quote to
> just before the second, ie starting with '192.168.1.101' and
> ending with '789.0.2', with the immediately following (no
> white space) unquoted text 'fCannotTakeover' appended
>         '=='             (blank seperated)
>         'priority"
>         '=='
> a string starting with critical, with the quoted string from
> 'SNMP-COMMUNITY' to 'Community.0 ' (including the blank), the
> unquoted string 'public', and the null quoted string "" all
> appended.
>
>  > TRAP='192.168.1.101 192.168.1.101 SNMPv2-MIB::sysUpTime.0
>  > 14:13:02:57.06 SNMPv2-MIB::snmpTrapOID.0 SNMPv2-SMI::enterprises.
>  > 789.0.13 SNMPv2-SMI::enterprises.789.0.2"cfCannotTakeover == 1
>  > priority == critical" SNMP-COMMUNITY-MIB::snmpTrapAddress.0
>  > 192.168.1.101 SNMP-COMMUNITY-MIB::snmpTrapCommunity.0 "public"'
>  > HOST=$(echo "$TRAP" | awk '{print $1}')
>  > SEVERITY='critical'
>  > /root/mk/services.py $HOST $SEVERITY \"$TRAP\"
>
>         Here, the variables are expanded, and then split into
> arguments on white space unless quoted. The backslashes protect
> the double quotes so they are treated as normal characters, so
> the $TRAP variable is also split into arguments on white space.
> Quotes resulting from the substitution of $TRAP are also protected
> (ie are treated as ordinary characters).
>
> The result is
>
>         '192.168.1.101"   (From $HOST)
>         'critical'        (From $SEVERITY)
>         '"192.168.1.101'  (Leading '"' from \", rest from
>                            $TRAP, blank seperated)
>         '192.168.1.101'   (from $TRAP, blank seperated)
>         'SNMPv2-MIB::sysUpTime.0'
> and so on for the rest of the $TARP string, splitting it at
> white space. The last part of $TRAP, '"public"', has a double
> quote appended from the \".
>
> Python is giving exactly what the shell has given it in both cases.
>
> Charles

ok, thanks for the answers. I try to hand over the 3rd part (the long
trap) as one cmd argument. I will ask in a shell ng. Thanks again.

Cheers

Marcus