Removed opened port in ufw
Answer:
If you have opened a port using the ufw command in Ubuntu, but now you want to delete it, you can..
# sudo ufw delete allow 8080/tcp
And then do a reload
# # sudo ufw reload
That's all.
Jan 202012
How to perform a reverse DNS lookup in Linux
Answer:
To perform a reverse DNS lookup for a domain in Linux, you can use the dig command, e.g.
# dig -x 8.8.8.8
; <<>> DiG 9.7.0-P1 <<>> -x 8.8.8.8
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 59808
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;8.8.8.8.in-addr.arpa. IN PTR
;; ANSWER SECTION:
8.8.8.8.in-addr.arpa. 86328 IN PTR google-public-dns-a.google.com.
..
How to get the MD5 checksum of a file under Mac OSX
Answer:
To get the MD5 checksum of a file under Mac OSX, like the md5sum command in Linux, you can use:
# md5 my-file.zip
How to uncompress a WAR file using command
Answer:
To un-compress a Java Web Archives file (*.war), you can use the command
# jar xvf my-app.war
Import private key into Mac's KeyChain
Answer:
To import a private key e.g. key.p12 into your login keychain, use the command:
# security import key.p12 -k ~/Library/Keychains/login.keychain
