I ended up doing exactly that - writing a TCL script. It's not perfect, but it got a similar job done that I pressingly needed it for.
That other task: write a change, that would be covered by my organization's formal change control process, to convert set of VLANs from {set a} to {set b}, where {set a} and {set b} had a strict 1:1 mapping. This was for a Nexus environment using FEX and FabricPath, so the available switchport modes I needed to contend with were access, trunk, fabricpath, and fex-fabric. It helped that all VLANs 1-4094 were configured, and pre-defined as mode fabricpath.
For this, I didn't need the script to identify the old -> new configuration, I just needed to identify mode trunk and mode access ports that were using VLANs in {set a}, and which VLANs each port used; and I could ignore ports that were mode fabricpath or mode fex-fabric.
Here's the script I rote. Again - there's issues with the script and it would need to be cleaned up to use on a recurring basis. But I only needed it one-time, and I haven't written "real" code in the 20years since I graduated college, so whatever.
This will output all the intermediary processing, since this is an in-line script. invoking tclsh with a URL would drop all that, but due to the restrictions organizationally imposed for formal change control, I needed to avoid reliance on a remote (tftp:// or scp:// or whatever) or local (sup-bootdisk:// etc) datastore.
The command "cli" could be replaced with "exec" to make it more portable... eh good enough for here.
# no idea why, but every time a CLI output is captured, the first line never evaluates properly
# this script accounts for that by including a single extra line of input, and discarding it.
#
# the "counter" trick used here is ugly, but works since the loops always re-start when counter=1
set VLAN_SET_A [list 102 122 232 242 243 246 259 283 286 288 334 341 346 356 358 373 375 385 405 406 410 411 421]
proc getaccessvlan {interface} {
set counter 0
foreach line [cli "show interface $interface switchport | inc Switchport:|Access.Mode.VLAN | cut -d ' ' -f 6"] {
if {$counter == 0} {
set counter 1
continue
}
return [string trim $line]
}
}
proc gettrunkvlanlist {interface} {
global VLAN_SET_A
set return_list {}
set counter 0
foreach line [cli "show interface $interface switchport | inc Switchport:|Trunking.VLANs.Allowed | cut -d ' ' -f 6"] {
if {$counter == 0} {
set counter 1
continue
}
foreach vlan_in_list [split [string trim $line] ","] {
if {[llength [split $vlan_in_list "-"]] == 1} {
if {[lsearch $VLAN_SET_A $vlan_in_list] != -1} {
lappend return_list $vlan_in_list
}
} else {
set vlan_to_add [lindex [split $vlan_in_list "-"] 0]
while {$vlan_to_add <= [lindex [split $vlan_in_list "-"] 1]} {
if {[lsearch $VLAN_SET_A $vlan_to_add] != -1} {
lappend return_list $vlan_to_add
}
incr vlan_to_add
}
}
}
}
return $return_list
}
set output {"================\nSTART EVALUATION HERE\n================"}
# begin main function
set counter 0
foreach interface [cli "sh int status | inc ^\[EP\] | egrep inv \"f-path| 1 \" | cut -d ' ' -f 1"] {
if {$counter == 0} {
set counter 1
continue
}
set counter 0
puts "evaluating interface $interface"
foreach int_mode [cli "show interface $interface switchport | inc \"Operational.Mode:|Switchport:\" | cut -d ' ' -f 5"] {
if {$counter == 0} {
set counter 1
continue
} else {
set int_mode [string trim "$int_mode"]
if {$int_mode eq "access"} {
set access_vlan [getaccessvlan "$interface"]
if {[lsearch $VLAN_SET_A $access_vlan] != -1} { lappend output "$interface is an access port on VLAN of concern: $access_vlan" }
} elseif {$int_mode eq "trunk"} {
set trunk_vlan_list [gettrunkvlanlist "$interface"]
if {[llength $trunk_vlan_list] > 0} { lappend output "$interface is a trunk port, that includes these VLANs of concern: $trunk_vlan_list" }
} else { lappend output "$interface is indeterminate" }
}
}
}
foreach line $output {
puts "$line"
}
