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for-loopawksedldapsubdomain

Auto-create DC= fields for LDAP from domain or subdomain

Via BASH script, I'm automatically constructing a string like: DC=us,DC=earth,DC=com for LDAP domain components. But, I won't know how many subdomain components a domain might have.

For example:

  • dub.sub.domain.tld needs DC=dub,DC=sub,DC=domain,DC=tld
  • sub.domain.tld needs DC=sub,DC=domain,DC=tld
  • domain.tld needs DC=domain,DC=tld

But, I don't know which one I'll have, and I need to automatically create this string.

My current solution is:

# The variable we got somehow
indomain="dub.sub.domain.tld"

#IFS='.' #Please no, sed instead...
# Create a loopable list with space as the IFS
domaincomponents=$(echo $indomain | sed 's/\./ /g')

# Process each domain component
finalstring=""
for component in $domaincomponents; do
  finalstring=DC=$component,$finalstring
done

# Remove the trailing ,
finalstring=$(echo $finalstring | sed 's/\(.*\),/\1 /')

Result: $finalstring = DC=tld,DC=domain,DC=sub,DC=dub

...which is in reverse

Not only does this produce the string backwards; it seems over-processed and that a tool like awk could do a cleaner job.

Is there a better way?

I am assuming that DC= in LDAP can go as deep as any subdomain name; correct me if I'm wrong.

Solution

  • With sed:

    echo 'dub.sub.domain.tld' | sed 's/^/DC=/; s/\./,DC=/g'

    Output:

    DC=dub,DC=sub,DC=domain,DC=tld