Useful Linux commands

from here

# 1. redo last command but as root
sudo !!

# 2. open an editor to run a command
ctrl+x+e

# 3. create a super fast ram disk
mkdir -p /mnt/ram
mount -t tmpfs tmpfs /mnt/ram -o size=8192M

# 4. don't add command to history (note the leading space)
 ls -l

# 5. fix a really long command that you messed up
fc

# 6. tunnel with ssh (local port 3337 -> remote host's 127.0.0.1 on port 6379)
ssh -L 3337:127.0.0.1:6379 root@emkc.org -N

# 7. quickly create folders
mkdir -p folder/{sub1,sub2}/{sub1,sub2,sub3}

# 8. intercept stdout and log to file
cat file | tee -a log | cat > /dev/null

# bonus: exit terminal but leave all processes running
disown -a && exit

# A. Delete all emails from bash
cat /dev/null > /var/spool/mail/root

# 11. Show PID program over port 5432
netstat -vanp tcp | grep 5432

# 12. Show PID program over port 5432
lsof -i tcp:5432

# 13. Stop postgres database on mac.sarch data folder
su postgres
/Library/PostgreSQL/9.5/bin/pg_ctl -D  /Library/PostgreSQL/9.5/data stop