for creating bulk categories

createtag.sh

#!/bin/bash
count=$1
for i in $(seq $count); do
    govc tags.create -c "testtagscachecategory"$i "tagscache"$i
done

createtagcategory.sh

#!/bin/bash
count=$1
for i in $(seq $count); do
    govc tags.category.create -d "testcache"$i "testtagscachecategory"$i
done

destroycategory.sh

#!/bin/bash
count=$1
for i in $(seq $count); do
    govc tags.category.rm  "testtagscachecategory"$i

done

destroytag.sh

#!/bin/bash
count=$1
for i in $(seq $count); do
    govc tags.rm -f -c "testtagscachecategory"$i "tagscache"$i

done

util_test_vmc

export GOVC_URL=https://xxx.xxxx-xx-xxx-xxx.vmwarevmc.com
export GOVC_USERNAME=xxxx@xxxx.xyz
export GOVC_PASSWORD=xxxxxxxx
export URL=https://xxxxxx.com

Export above variables and then pass the count to the above shell scripts to create categories 
Refer for more - https://github.com/vmware/govmomi/blob/master/govc/USAGE.md 
to Download cli use - https://github.com/vmware/govmomi/blob/master/govc/README.md#binaries