Useful linux commands

This is the command which can be used to show all the users with all the grants on mysql from command line.

select user,host,password from mysql.user order by user;

Useful command to add ssh key.

cat >> ~/.ssh/authorized_keys 

SSH chain login.

ssh -A -t user@server1 ssh -A -t user@server2 ssh -A user@server3 

Find in specific files and replace

grep -rl --include=*.xml oldname /var/www/html | xargs sed -i 's/oldname/newname/g'

Test CPU waiting time because of the IOPS

iostat -mx 1

Add ssh key to a remote server with a single command

cat ~/.ssh/ | ssh user@hostname 'cat >> .ssh/authorized_keys && chmod 600 .ssh/authorized_keys && restorecon -R .ssh'

Login to a user which doesn’t have shell access (nologin)

 su -s /bin/bash USER 

Remove server from knows_hosts

ssh-keygen -f "~/.ssh/known_hosts" -R 192.168.0.xx

Working with git tags

Create a tag

git tag test_1000

Push tags to git

git push --tags

Delete a git tag

git tag -d test_1000
git push origin :refs/tags/test_1000   or   git push origin ::refs/tags/test_1000

Generate hash passwords for puppet

openssl passwd -1

RDP from Linux to Windows with clipboard sync

rdesktop -u USERNAME -k en-us -p PASSWORD -a 16 -z -5 -P IP_ADDRESS -d DOMAINA.NAME -g 1366x1024 -5 -K -r clipboard:CLIPBOARD

Grep and sort logs

grep -rni "expression" access.log | grep -i login |cut -f 4 -d ' '|sort|uniq -c|sort -nr

Attach to docker container

docker attach --sig-proxy=false 0cd6bd960475
docker exec -it 0cd6bd960475 bash

Download with curl

curl -o /etc/yum.repos.d/rhel-pulp.repo

Git remove deleted files

git ls-files --deleted -z | xargs -0 git rm 

Kubernetes container with bash exec

kubectl exec  -it `kubectl get pods --namespace NAMESPACE | grep -i POD | awk '{print $1}'` -c NGINX  bash --namespace NAMESPACE

Netcat replacement

nmap -p 1-10 HOST

Create archives with tar password protected using gpg

tar -czvpf - FOLDERS_FILES_TO_ARCHIVE | gpg --symmetric --cipher-algo aes256 -o ARCHIVE_NAME.gz.gpg


gpg -d ARCHIVE_NAME.gz.gpg | tar -xvzf -


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