Using awk:

BEGIN { OFS = "," }

{ servers[$1] = (servers[$1] == "" ? $2 : servers[$1] "," $2 ) }

END {
    $0 = ""
    for (domain in servers)
        $(++n) = sprintf("\"%s(server:%s)\"", domain, servers[domain])

    print
}

This would add the servers as a comma-delimited string to the specific domain in the main block while parsing the input file. This is done by modifying the servers array which holds the servers for a particular domain (the domain is the key in the array).

In the END block, we loop over all keys/domains in the servers array and create an output record in the specified format.

Running this on the supplied data:

$ awk -f script.awk names.txt
"TADDomain(server:TADServer_1)","ABCDomain(server:ContractABCServer_1,ABC_server1)","LinkDomain(server:CoreLinkServer_1)"

A mostly equivalent bash script (requires bash 4.3+ for the associative array):

declare -A servers

while read domain server; do
    servers[$domain]+="${servers[$domain]:+,}$server"
done <names.txt

for domain in "${!servers[@]}"; do
    out+="${out:+,}\"$domain(server:${servers[$domain]})\""
done

printf '%s\n' "$out"

... but see "https://unix.stackexchange.com/questions/169716".

(Updated to correct the output format)

Using awk:

BEGIN { OFS = "," }

{ servers[$1] = (servers[$1] == "" ? "server:" $2 : servers[$1] "," "server:" $2 ) }

END {
    $0 = ""
    for (domain in servers)
        $(++n) = sprintf("\"%s(%s)\"", domain, servers[domain])

    print
}

This would add the servers as a comma-delimited string to the specific domain in the main block while parsing the input file. This is done by modifying the servers array which holds the servers for a particular domain (the domain is the key in the array).

In the END block, we loop over all keys/domains in the servers array and create an output record in the specified format.

Running this on the supplied data:

$ awk -f script.awk names.txt
"TADDomain(server:TADServer_1)","ABCDomain(server:ContractABCServer_1,server:ABC_server1)","LinkDomain(server:CoreLinkServer_1)"

A mostly equivalent bash script (requires bash 4.3+ for the associative array):

declare -A servers

while read domain server; do
    servers[$domain]+="${servers[$domain]:+,}server:$server"
done <names.txt

for domain in "${!servers[@]}"; do
    out+="${out:+,}\"$domain(${servers[$domain]})\""
done

printf '%s\n' "$out"

... but see "https://unix.stackexchange.com/questions/169716".

Using awk:

BEGIN { OFS = "," }

{ servers[$1] = (servers[$1] == "" ? $2 : servers[$1] "," $2 ) }

END {
    $0 = ""
    for (domain in servers)
        $(++n) = sprintf("\"%s(server:%s)\"", domain, servers[domain])

    print
}

This would add the servers as a comma-delimited string to the specific domain in the main block while parsing the input file. This is done by modifying the servers array which holds the servers for a particular domain (the domain is the key in the array).

In the END block, we loop over all keys/domains in the servers array and create an output record in the specified format.

Running this on the supplied data:

$ awk -f script.awk names.txt
"TADDomain(server:TADServer_1)","ABCDomain(server:ContractABCServer_1,ABC_server1)","LinkDomain(server:CoreLinkServer_1)"

Using awk:

BEGIN { OFS = "," }

{ servers[$1] = (servers[$1] == "" ? $2 : servers[$1] "," $2 ) }

END {
    $0 = ""
    for (domain in servers)
        $(++n) = sprintf("\"%s(server:%s)\"", domain, servers[domain])

    print
}

This would add the servers as a comma-delimited string to the specific domain in the main block while parsing the input file. This is done by modifying the servers array which holds the servers for a particular domain (the domain is the key in the array).

In the END block, we loop over all keys/domains in the servers array and create an output record in the specified format.

Running this on the supplied data:

$ awk -f script.awk names.txt
"TADDomain(server:TADServer_1)","ABCDomain(server:ContractABCServer_1,ABC_server1)","LinkDomain(server:CoreLinkServer_1)"

A mostly equivalent bash script (requires bash 4.3+ for the associative array):

declare -A servers

while read domain server; do
    servers[$domain]+="${servers[$domain]:+,}$server"
done <names.txt

for domain in "${!servers[@]}"; do
    out+="${out:+,}\"$domain(server:${servers[$domain]})\""
done

printf '%s\n' "$out"

... but see "https://unix.stackexchange.com/questions/169716".