Use sed to replace IP address with hostname in log output
I am trying to replace an IP address in a dnsmasq logfile with its hostname. The logfile is being 'watched' with the command 'tail -f /var/log/dnsmasq.log' on the console and I want to pipe the output into sed to replace the IP address with the hostname on ONLY the lines that contain the text 'query'. The IP address is always at the end of these lines.
An example line is:
Apr 1 00:47:43 dnsmasq[1004]: query[A] gs-loc.apple.com from 10.1.1.188
I believe the command would be in the form of:
tail -f /var/log/dnsmasq.log | sed -e "s/'regex'/$(dig +short -x $1)/g"
The 'regex' needs to identify the lines containing the string "query", extract the IP address from the end of that line and store it (somehow) in a variable - I used the notation $1 here - that is used in the replace expression with dig.
I hope this makes sense. I would be very grateful for any help as the regex is beyond me at the moment.
sed
edited 17 mins ago
John1024
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asked 23 mins ago
deanodleydeanodley
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I am trying to replace an IP address in a dnsmasq logfile with its hostname. The logfile is being 'watched' with the command 'tail -f /var/log/dnsmasq.log' on the console and I want to pipe the output into sed to replace the IP address with the hostname on ONLY the lines that contain the text 'query'. The IP address is always at the end of these lines.
An example line is:
Apr 1 00:47:43 dnsmasq[1004]: query[A] gs-loc.apple.com from 10.1.1.188
I believe the command would be in the form of:
tail -f /var/log/dnsmasq.log | sed -e "s/'regex'/$(dig +short -x $1)/g"
The 'regex' needs to identify the lines containing the string "query", extract the IP address from the end of that line and store it (somehow) in a variable - I used the notation $1 here - that is used in the replace expression with dig.
I hope this makes sense. I would be very grateful for any help as the regex is beyond me at the moment.
sed
edited 17 mins ago
John1024
48.2k5113128
asked 23 mins ago
deanodleydeanodley
1
New contributor
deanodley is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
I am trying to replace an IP address in a dnsmasq logfile with its hostname. The logfile is being 'watched' with the command 'tail -f /var/log/dnsmasq.log' on the console and I want to pipe the output into sed to replace the IP address with the hostname on ONLY the lines that contain the text 'query'. The IP address is always at the end of these lines.
An example line is:
Apr 1 00:47:43 dnsmasq[1004]: query[A] gs-loc.apple.com from 10.1.1.188
I believe the command would be in the form of:
tail -f /var/log/dnsmasq.log | sed -e "s/'regex'/$(dig +short -x $1)/g"
The 'regex' needs to identify the lines containing the string "query", extract the IP address from the end of that line and store it (somehow) in a variable - I used the notation $1 here - that is used in the replace expression with dig.
I hope this makes sense. I would be very grateful for any help as the regex is beyond me at the moment.
sed
edited 17 mins ago
John1024
48.2k5113128
asked 23 mins ago
deanodleydeanodley
1
New contributor
deanodley is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
I am trying to replace an IP address in a dnsmasq logfile with its hostname. The logfile is being 'watched' with the command 'tail -f /var/log/dnsmasq.log' on the console and I want to pipe the output into sed to replace the IP address with the hostname on ONLY the lines that contain the text 'query'. The IP address is always at the end of these lines.
An example line is:
Apr 1 00:47:43 dnsmasq[1004]: query[A] gs-loc.apple.com from 10.1.1.188
I believe the command would be in the form of:
tail -f /var/log/dnsmasq.log | sed -e "s/'regex'/$(dig +short -x $1)/g"
The 'regex' needs to identify the lines containing the string "query", extract the IP address from the end of that line and store it (somehow) in a variable - I used the notation $1 here - that is used in the replace expression with dig.
I hope this makes sense. I would be very grateful for any help as the regex is beyond me at the moment.
sed
sed
edited 17 mins ago
John1024
48.2k5113128
asked 23 mins ago
deanodleydeanodley
1
New contributor
deanodley is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 17 mins ago
John1024
48.2k5113128
asked 23 mins ago
deanodleydeanodley
1
New contributor
deanodley is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 17 mins ago
John1024
48.2k5113128
edited 17 mins ago
John1024
48.2k5113128
edited 17 mins ago
John1024
48.2k5113128
48.2k5113128
asked 23 mins ago
deanodleydeanodley
1
New contributor
deanodley is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 23 mins ago
deanodleydeanodley
1
asked 23 mins ago
deanodleydeanodley
1
1
New contributor
deanodley is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
deanodley is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
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