Here is a list of useful unix commands or code parts. Who does not know it? You have a problem and looking for a solution where you find at stack overflow or similar pages? Here I collect all the commands that I have encountered over time or whose switch I simply can not remember (or want).
- How do I find all files containing specific text?
grep -rnw '/path/to/somewhere/' -e 'pattern'
- How i change the default file permissions (mask that controls file permissions)
umask
- Untar (unzip) file/folder
tar -zxvf archive.tar.gz
- Tar (zip) file/folders
tar -cvzf archive.tar.gz file1 file2
- Copy files via rsync from one host to another
rsync -avz [USER@]HOST:SOURCE [USER@]HOST:DEST
rsync -avz [USER@]HOST:SOURCE rsync://[USER@]HOST[:PORT]/DEST
rsync -avz -e "ssh -p 12345" LOCAL/SOURCE [USER@]HOST:DEST
- Using rsync with sudo on the destination machine
- Find out the path to rsync:
which rsync
- Edit the /etc/sudoers file:
sudo visudo
- Add the line
<username> ALL=NOPASSWD:<path to rsync>
, where username is the login name of the user that rsync will use to log on. That user must be able to use sudo
- Find out the path to rsync:
Then, on the source machine, specify that sudo rsync shall be used:
rsync -avz --rsync-path="sudo rsync" SOURCE [USER@]HOST:DEST
- Preserve SSH_AUTH_SOCK (Environment Variables) When Using sudo
sudo --preserve-env=SSH_AUTH_SOCK -s
- nslookup missing? Install dig
sudo apt-get install dnsutils
- find without “Permission denied”
find / -name 'filename.ext' 2>&1 | grep -v "Permission denied"
- flush dns cache
sudo systemd-resolve --flush-caches
- show open ports
netstat -tulpn
- Directory size
du -sh /var
du -shc /var/*
du -h --max-depth=1 /var
du -sh /var/lib/docker/containers/*/*.log
- Search multiple PDF files for a “needle”
pdfgrep -i needle haystack*.pdf
- Show hidden files with ls
ls -lar
- Redirect STDOUT and STDERR to a file
nice-command > out.txt 2>&1
- Installs your SSH public key to a remote host
sh-copy-id 'user@remotehost'
- A command-line system information tool
neofetch
- Show disk usage, folder size, items per folder, find big directorys, … with ncdu
ncdu
- Display Network usage
iftop or iptraf
- Cleanup Docker
docker system prune --help
- Find and repair disk errors on ext (ext2, ext3 and ext4) filesystems
sudo e2fsck -f </dev/sda2>