Cheat Sheet
Useful bash commands and snippets.
apt
Install specific package version
apt-cache policy kubelet
apt-get install kubelet=1.13.4-00
Hold version
apt-mark hold kubelet kubeadm kubectl
Remove hold version
apt-mark unhold kubelet kubeadm kubectl
crontab
List crontab for all users
for user in $(cut -f1 -d: /etc/passwd); do crontab -u $user -l; done
du
Hidden files
du -sch .[!.]* * |sort -h
Sort by size
du -hsc * |sort -h
ncurses interface
sudo apt install ncdu
ncdu
find
find and du -hsc
find . \
-name "*.txt" \
-maxdepth 2 \
-type d \
-exec du -csh --block-size=1M {} \;
find and rm
find . -name "server.log-2018*" \
-print0 | xargs -0 rm -f
Find and sed
find . -type f -print0 | xargs -0 sed -i 's/OLD/NEW/g'
Tools
fzf
grep
Sort by second column:
grep -air "count-" file-name* |sort -k2
Hard drive management
List all hard drives and partitions:
sudo lsblk -o NAME,FSTYPE,SIZE,MOUNTPOINT,LABEL
journalctl
Get all logs
Get 20 most recent:
journalctl -n 20
Get process logs
journalctl -u kubelet
Processes management
Check if process is running
#!/bin/bash
service=mongod
if (( $(ps -ef | grep -v grep | grep $service | wc -l) > 0 ))
then
echo "$service is running!!!"
else
/etc/init.d/$service start
fi
Swap management
Create swap partition
sudo /bin/dd if=/dev/zero of=/var/swap.0 bs=1M count=1024
sudo /sbin/mkswap /var/swap.0
sudo /sbin/swapon /var/swap.0
echo "/var/swap.0 swap swap defaults 0 0" >> /etc/fstab
Disable swap
sudo swapoff -a
systemctl
Check if process is enable
systemctl is-enabled PROCESS-NAME-HERE
List all services
systemctl list-units --type service --all
telnet
Client close connection
Input ctrl+]
Then execute:
close
wget
Backup entire website.
wget \
--recursive \
--no-clobber \
--page-requisites \
--html-extension \
--convert-links \
--restrict-file-names=windows \
--domains devops.buzz \
--no-parent \
https://www.devops.buzz/public/
References
https://www.linuxjournal.com/content/downloading-entire-web-site-wget
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