Below you can found a list of commands that saved my life in certain critical conditions. I hope that these commands can help you if you are in the same condition.
Networking
- Get MAC address of a network card (version 1)
# ifconfig eth0 | grep -o -E '([[:xdigit:]]{1,2}:){5}[[:xdigit:]]{1,2}'- Get MAC address of a network card (version 2)
# ifconfig eth0 | awk '/HWaddr/ {print $5}'- List network card names
# basename -a /sys/class/net/*
Storage, Disk and files
- Disk usage without mount points
# du -hx
- How to less last file in a directory ?
# ls -1 -t | head -1 | xargs less
- List file using ls command with full path
# ls -1 $PWD/filename.ext
- Exclude from listing file with particular extension
# ls -dl !(*.xml|*.txt|*.pdf|*.sql)
- Create a file with a specific size
# truncate -s 14M filename
Miscellaneous
- Protect a zip file on command line.
# zip -e "file_name".zip "list_of_files"
- Format date in another locale
# LC_ALL=us date -d'now-2 hours' +'%b %d %H:%M'
- Execute local bash script on remote host
# ssh [email protected] 'bash -s' < local.cmd
- Get authentication failure from /var/log/auth.log
# grep "authentication failure;" /var/log/auth.log | \
egrep -o "[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}" | \
sort | uniq -c | sort -nr | less
- Append current date to a file every 1 second
# nohup bash -c "while sleep 1; do date >> /home/user/test.txt; done" &
- Force logrotate
# logrotate --force $CONFIG_FILE
- Rsync data
# rsync -av /var/lib/mysql /mnt/mysql/
- Send test mail
# echo "Subject: sendmail test" | sendmail -v [email protected]
- Create symbolic or hard link with cp command
~#: cp -s source dest # for symbolic link
~#: cp -l source dest # for hard link
