Commands that I would not otherwise use/remember
- will eventually format this with fancy hyperlinks and the like*
General commands
sudo !! (run last command as root (!! means to run the last command))
pkill -9 -f “program” (kill all instances of a program)
Source .bashrc (enable the updated bashrc)
ls -laht (long,all,humanreadable,time)
du -sh file_path (see size of directory)
awk '{print $3;}' (this will print the 3rd word of the output, if you ran it against this sentace it will return the word print)
using &! after running a command will put it fork the command to the background (&) and then disown (remove from the 'jobs' list) the command (!)
nl <afile> (it's like cat but with line numbers !)
text minpulation
cut -c 4- <file> (remove first 4 characters from a line)
Status commands
uname -a (show kernel version etc)
less (pipe commands to this for easy reading (ls -la | less)
df -h (drive information)
free (memory information)
ps -ef (list processes.)
lsof (list open files)
lsof -Pi:<portnum> (list services running on port) (run as root or sudo)
ps aux (current processes, aux flags = a - processs for all users, u - display process owner, x - show processes not attached to terminal)
smartctl -a /dev/sda (lists abundence of information relating to hardrive health
dmesg -H (dmesg with time stamps and in $PAGER (less default))
ps aux --sort=-%mem | awk 'NR<=10' (find processes using the most memory)
nmcli device wifi list (show wifi stats)
hwclock (show the hardware clock status)
hwclock -w (sync hardware clock with the current date)
strace -p $(pgrep broken_script.sh) see what calls "broken_script.sh" is doing
lsof -i | grep LISTEN (show what ports are listening and therefore ready to accept accept data)
systemd
systemctl list-unit-files | grep enabled (startup programs)
systemd-analyze (boot time)
systemd-analyze blame (time each service took to boot)
user commands
usermod -aG wheel *username* (add user to the wheel group)
chage -d 0 <username> (make sure the user changes their password on login)
file system
fuesr -cv (check what
es a mount is using, useful when umounting)
grep
you could just read the man page
grep -i (case sensitive)
grep -v (!=)
kill
kill pid (kill a process)
kill -STOP pid (stop (freeze) a process)
kill -CONT pid (resume a stopped process)
kill -INT pid(ctrl c)
Kill -KILL pid (also use kill -9. This absoulty destroys a process. Forcefully removes it from ram and ends its life without giving it any chance at shutting itself down gracefully)
find
find . -name "thing you want to delete" -delete (use find to delete things that you have found)
find . -name '*.pyc' -delete (an example, deleting anything that ends in .pyc)
DD
data duplicatior(destroyer)
the if and of stand for input file and output file
dd if=/dev/sda of=/dev/sdb (clone one hdd to another hdd)
dd if=/dev/sda4 of=~/hdadisk.img (backup of sda4 partition and name it hdadisk.img)
dd if=hdadisk.img of=/dev/sdb3 (restore from .img file to dev/sdb3)
dd if=/dev/zero of=/dev/sdb (wipe /dev/sdb. /dev/zero is a special file that provides null characters)
status=progess (add this to the end of a dd command to see the progess of the commadn)
Rsync
rsync -a ~/dir1 username@remote_host:destination_directory ( synch to a remote host (push))
rsync -a username@remote_host:/home/username/dir1 place_to_sync_on_local_machine ( sync
from remote to local (pull))
Screen commands
"ctrl a" is the modifyer so screen knows a command is coming
screen (start screen)
screen -r (reattach screen)
ctrl ac (move between screens)
ctrl ak (kill current screen)
ctrl aw (list screens)
ctrl an (new screens)
ctrl ad (detatch back to shell)
ctrl a[ (enters copy mode (enter once to copy and enter again to save it to clipboard))
ctrl a] (paste what is copied)
ctrl a, a (send commands to nested screen)
ctrl a, | - split the session (ctrl a tab to switch between them)
ctrl a, S – splits the session differnetly
ctrl a, X - Removes a "split"
ctrl a, t - Time & Load average
screen -X -S SCREENID kill (kill attached screen session)
screen -D -r (reconnect to attached screen session)
ctrl a :number <num> (reorder screen to be number <num)
ctrl a, x (Screen sharing, you can join someone elses screen session without detaching them!)
Vim
sudo -e file (edit file with root permissions but keep user vimrc)
:w !sudo tee % (save readonly file not opended as root)
pandoc -f docx -t rst /patht/to/file.docx | vim - (edit word docs in vim, can change docx to odt for libreoffice)
:7,15s/^/#/ (replace the start of lines 7 - 15 with a # (usefule for block commenting for example))
in vim terminal: scroll up with `ctrl+w N`, press `i` or `a` to get out of this scroll mode
Splits
resize height with ctrl+w + -
resize width with ctrl+w < >
can use things like ctrl+w 100 + to do 100 of that action
ctrl+w = resize everything equally.
iptables
ip6tables for ipv6
iptables -t filter -A INPUT -s x.x.x.x -j REJECT (block the specified ip.)
-t table to use -A append -s source ip -j block method(REJECT, DROP).
Git soon (tm)
XTerm
shift insert (copy/paste)
fail2ban
fail2ban-client status set <jailname (sshdisdefault)> unbanip x.x.x.x (unbans target ip)
Tar
Tar -xzf ((e)xtract ze file!)
Tar -czf (compress ze file!)
ssh
$ ssh -L 9000:imgur.com:80 [email protected] (ssh tunneling (localhost:portnum(9000) to vist site))
To exit out of a frozen ssh session press: 'enter' ~ .
ssh -J user@jumpbox -X user@box (Jump through first to second, this also fowards X but thats not needed)
rdesktop
rdesktop -g 1920x1080 -K -u administrator 192.168.100.200 -r disk:disk/path/to/mount (mount "/path/to/mount/" on remote windows machine and also connect to it as the admin user)
ss
replaces netstat
ss (shows all tcp,udp and unix socket information)
ss -l (show current listing sockets)
ss -t -u -x (these flags are for showing tcp,udp and unix connections)
ss -a (need to add to show listing sockets as well. Default is only established connections)
ss dst x.x.x.x (show how you are connecting to an ip)
tcpdump
tcpdump not port 443 (show packets that do not come from 443. This can be done with mutiple ports as well)
tcpdump - "interface" (show packets from that a certain interface)
tcpdump "protocol" (show only certain protocol. see /etc/protocols for a list
docker
docker pull "image" (download docker images)
docker images (list all images downloaded)
docker start "image id" (stat image in background)
docker attach "image id" (reattach docker image to the terminal)
docker run "image" (run a docker image. This creates a new container which you then need to save by commiting it.)
docker run -it "image" (run a docker image and access the shell)
docker commit -m "message" -a "author" "container-id" "repo/name" (commit a new docker image)
docker commit "containerid" "repo/name" (simplier docker commit)
docker ps -l (list containerid)
docker ps (list all running containers)
docker ps -a (list all containers)
docker stop "container-id" (stop a running container)
docker rmi "image" (remove docker image)
docker system prune --volumes
docker-compose docker-compose up -d docker-compose logs docker-compose down --rmi all
ffmpeg
ffmpeg -f x11grab -s 1366x768 -i :0.0 out.mkv (record screen, change size to be appropite to your display)
Misc
python -m SimpleHTTPServer [port] (start a webserver serving the current directory)
python -m http.server [port] (python3 of the above command)
echo -n foobar | sha256sum (generate sha256 hash if "foobar" -n stops echo producing a trailing newline)
badblocks -v /dev/sda (show badblocks on drive)
pygmentize (cat with syntax highlighting)
cd /usr/src/linux
make menuconifg (this command allows you to configure the kernel modules. You need to be in /usr/src/linux to do it)
wget --mirror --convert-links --adjust-extension --page-requisites --no-parent (download webpage to read later)
indent <file> -kr -i8 (idnet code to linux kernel coding style)
dmidecode -s system-serial-number (get dell service tag)
echo $((1 + 1)) - preform math in the shell !
Scripting
xargs <command> (will run against stdin line by line)
ffmpeg -i input.mp4 -acodec libvorbis -vcodec libtheora -f ogv output.ogv (convert mp4 to ogg)
Document conversion
mainly pandoc related stuff
pandoc -w mediawiki file.md -o file.wiki (convert from markdown markup to mediawiki markup)
pandoc --tos -s file.md -o file.html (convert from markdown to html. This will also generate a table of contents out of your markdown headers)
Fun
This should be a simulate a cointoss 100 times then tell you how many times it landed on heads
for some reason it does not always work, but it eventaully will if you keep running the command
shuf -r -n 100 -e Head Tail > headtail | grep "Head" headtail | wc -l
most used commands and percentages of them
history | awk '{CMD[$2]++;count++;}END { for (a in CMD)print CMD[a] " " CMD[a]/count*100 "% " a;}' | grep -v "./" | column -c3 -s " " -t | sort -nr | nl | head -n10
Gentoo-specific-commands Reference commands that I might need in the future this used to be its own repo but I did not think that was nessessary
Bluetooth
Bluetooth seems to be turned on by default (at least the btusb radio device is.) This saps a lot of power and is the top consumer of power in powertop when the system is idle
To turn it off:
emerge -av net-wireless/rfkill
rfkill block bluetooth
portage errors
when running emerge -av package_name, sometimes it says required by package www-clinet/w3m imlib for example
this means that you need to create a file name after the package_name /etc/portage/make.use directory and paste in the "required by package part of the error" This should work.
CentOS
install extexted packages
yum install epel-release
remove dump files
centos creates dump files by default. These can ocassionaly take up a lot of space. TO remove them
sudo find . -name "core.[0-9]*" -delete
configure networking
nmtui (easy mode)
Add a gpg key
rpm -Uvh <key.rpm>
rpm --import <key.txt>
Debian
get number of packages installed
dpkg -l
Fedora
*allow access to extended free and non free repos
sudo dnf install https://download1.rpmfusion.org/free/fedora/rpmfusion-free-release-$(rpm -E %fedora).noarch.rpm https://download1.rpmfusion.org/nonfree/fedora/rpmfusion-nonfree-release-$(rpm -E %fedora).noarch.rpm