Useful Commands (updated occationally)
I got tired of forgetting simplest of commands all the time and end up googling for it. So here is a copy of my dumps.
1 Passwords
Passwords are encrypted. Usually in these files. Can use cat or grep:
$ cat /etc/passwd
$ grep '^usernamehere' /etc/passwd
1.1 Linux Set or Change User Password
Must use:
- Lower case alphabetics
- Upper case alphabetics
- Digits 0 thru 9
- Punctuation marks/spacial characters
$ passwd
Changing password for {username}
(current) UNIX password:
Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully
1.2 Linux change password for other user account
$ sudo passwd {other_username}
Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully
1.3 Linux Change Group Password
$ sudo passwd -g sales
1.4 Forcing Linux user to change password at their next login
We can force users to change their password the next time they log in via GUI or CLI methods.
$ sudo passwd -e {username}
$ sudo passwd --expire {username}
Let us immediately expire an account’s password
$ sudo passwd -e username
passwd: password expiry information changed.
1.5 Locking and Unlocking user password of the named account
Users with a locked password are not allowed to change their password. To lock the user with password
$ sudo passwd -l {username}
To unlock the user with password
$ sudo passwd -u {username}
2. Add and Delete Users on Ubuntu
Add a user:
$ sudo adduser newuser
Set password prompts:
Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully
User information prompts:
Changing the user information for username
Enter the new value, or press ENTER for the default
Full Name []:
Room Number []:
Work Phone []:
Home Phone []:
Other []:
Is the information correct? [Y/n]
$ sudo groups newuser
Output
newuser : newuser
$ sudo usermod -aG sudo newuser
$ su - newuser
$ sudo some_command
$ cat /etc/sudoers
root ALL=(ALL:ALL) ALL
newuser ALL=(ALL:ALL) ALL # ADD THIS LINE
Delete a user:
$ sudo deluser newuser
or
$ sudo deluser --remove-home newuser
$ cat /etc/sudoers
root ALL=(ALL:ALL) ALL
newuser ALL=(ALL:ALL) ALL # DELETE THIS LINE
3. Some Useful Aliases and Functions
Here is some of the aliases I have in my ~/.bashrc. Use and adjust the aliases or functions that works for you best.
3.1 Handy Aliases
CLICK TO EXPAND
alias -='cd -'
alias ...=../..
alias ....=../../..
alias .....=../../../..
alias ......=../../../../..
alias ..q=exit
alias .src='source ~/.bashrc'
alias 1='cd -'
alias 2='cd -2'
alias 3='cd -3'
alias 4='cd -4'
alias 5='cd -5'
alias 6='cd -6'
alias 7='cd -7'
alias 8='cd -8'
alias 9='cd -9'
alias _='sudo '
alias afind='ack -il'
alias c.='code . > /dev/null'
alias cpu5='ps auxf | sort -nr -k 3 | head -5'
alias diff='diff --color'
alias e.='explorer.exe . || true'
alias egrep='egrep --color=auto --exclude-dir={.bzr,CVS,.git,.hg,.svn,.idea,.tox}'
alias extip='curl icanhazip.com'
alias fgrep='fgrep --color=auto --exclude-dir={.bzr,CVS,.git,.hg,.svn,.idea,.tox}'
# some git command shortcuts
alias g=git
alias ga='git add'
alias gaa='git add --all'
alias gam='git am'
alias gama='git am --abort'
alias gamc='git am --continue'
alias gams='git am --skip'
alias gamscp='git am --show-current-patch'
alias gap='git apply'
alias gapa='git add --patch'
alias gapt='git apply --3way'
alias gau='git add --update'
alias gav='git add --verbose'
alias gb='git branch'
alias gbD='git branch -D'
alias gba='git branch -a'
alias gbd='git branch -d'
alias gbda='git branch --no-color --merged | command grep -vE "^([+*]|\s*($(git_main_branch)|$(git_develop_branch))\s*$)" | command xargs g
alias gbl='git blame -b -w'
alias gbnm='git branch --no-merged'
alias gbr='git branch --remote'
alias gbs='git bisect'
alias gbsb='git bisect bad'
alias gbsg='git bisect good'
alias gbsr='git bisect reset'
alias gbss='git bisect start'
alias gc='git commit -v'
alias 'gc!'='git commit -v --amend'
alias gca='git commit -v -a'
alias 'gca!'='git commit -v -a --amend'
alias gcam='git commit -a -m'
alias 'gcan!'='git commit -v -a --no-edit --amend'
alias 'gcans!'='git commit -v -a -s --no-edit --amend'
alias gcas='git commit -a -s'
alias gcasm='git commit -a -s -m'
alias gcb='git checkout -b'
alias gcd='git checkout $(git_develop_branch)'
alias gcf='git config --list'
alias gcl='git clone --recurse-submodules'
alias gclean='git clean -id'
alias gcm='git checkout $(git_main_branch)'
alias gcmsg='git commit -m'
alias 'gcn!'='git commit -v --no-edit --amend'
alias gco='git checkout'
alias gcor='git checkout --recurse-submodules'
alias gcount='git shortlog -sn'
alias gcp='git cherry-pick'
alias gcpa='git cherry-pick --abort'
alias gcpc='git cherry-pick --continue'
alias gcs='git commit -S'
alias gcsm='git commit -s -m'
alias gcss='git commit -S -s'
alias gcssm='git commit -S -s -m'
alias gd='git diff'
alias gdca='git diff --cached'
alias gdct='git describe --tags $(git rev-list --tags --max-count=1)'
alias gdcw='git diff --cached --word-diff'
alias gds='git diff --staged'
alias gdt='git diff-tree --no-commit-id --name-only -r'
alias gdup='git diff @{upstream}'
alias gdw='git diff --word-diff'
alias gf='git fetch'
alias gfa='git fetch --all --prune --jobs=10'
alias gfg='git ls-files | grep'
alias gfo='git fetch origin'
alias gg='git gui citool'
alias gga='git gui citool --amend'
alias ggpull='git pull origin "$(git_current_branch)"'
alias ggpur=ggu
alias ggpush='git push origin "$(git_current_branch)"'
alias ggsup='git branch --set-upstream-to=origin/$(git_current_branch)'
alias ghh='git help'
alias gignore='git update-index --assume-unchanged'
alias gignored='git ls-files -v | grep "^[[:lower:]]"'
alias git-svn-dcommit-push='git svn dcommit && git push github $(git_main_branch):svntrunk'
alias gk='\gitk --all --branches &!'
alias gke='\gitk --all $(git log -g --pretty=%h) &!'
alias gl='git pull'
alias glg='git log --stat'
alias glgg='git log --graph'
alias glgga='git log --graph --decorate --all'
alias glgm='git log --graph --max-count=10'
alias glgp='git log --stat -p'
alias glo='git log --oneline --decorate'
alias globurl='noglob urlglobber '
alias glod='git log --graph --pretty='\''%Cred%h%Creset -%C(auto)%d%Creset %s %Cgreen(%ad) %C(bold blue)<%an>%Creset'\'
alias glods='git log --graph --pretty='\''%Cred%h%Creset -%C(auto)%d%Creset %s %Cgreen(%ad) %C(bold blue)<%an>%Creset'\'' --date=short'
alias glog='git log --oneline --decorate --graph'
alias gloga='git log --oneline --decorate --graph --all'
alias glol='git log --graph --pretty='\''%Cred%h%Creset -%C(auto)%d%Creset %s %Cgreen(%ar) %C(bold blue)<%an>%Creset'\'
alias glola='git log --graph --pretty='\''%Cred%h%Creset -%C(auto)%d%Creset %s %Cgreen(%ar) %C(bold blue)<%an>%Creset'\'' --all'
alias glols='git log --graph --pretty='\''%Cred%h%Creset -%C(auto)%d%Creset %s %Cgreen(%ar) %C(bold blue)<%an>%Creset'\'' --stat'
alias glp=_git_log_prettily
alias glum='git pull upstream $(git_main_branch)'
alias gm='git merge'
alias gma='git merge --abort'
alias gmom='git merge origin/$(git_main_branch)'
alias gmtl='git mergetool --no-prompt'
alias gmtlvim='git mergetool --no-prompt --tool=vimdiff'
alias gmum='git merge upstream/$(git_main_branch)'
alias gp='git push'
alias gpd='git push --dry-run'
alias gpf='git push --force-with-lease'
alias 'gpf!'='git push --force'
alias gpoat='git push origin --all && git push origin --tags'
alias gpr='git pull --rebase'
alias gpristine='git reset --hard && git clean -dffx'
alias gpsup='git push --set-upstream origin $(git_current_branch)'
alias gpu='git push upstream'
alias gpull='git pull origin master'
alias gpush='git push origin master'
alias gpv='git push -v'
alias gr='git remote'
alias gra='git remote add'
alias grb='git rebase'
alias grba='git rebase --abort'
alias grbc='git rebase --continue'
alias grbd='git rebase $(git_develop_branch)'
alias grbi='git rebase -i'
alias grbm='git rebase $(git_main_branch)'
alias grbo='git rebase --onto'
alias grbs='git rebase --skip'
alias grep='grep --color=auto --exclude-dir={.bzr,CVS,.git,.hg,.svn,.idea,.tox}'
alias grev='git revert'
alias grh='git reset'
alias grhh='git reset --hard'
alias grm='git rm'
alias grmc='git rm --cached'
alias grmv='git remote rename'
alias groh='git reset origin/$(git_current_branch) --hard'
alias grrm='git remote remove'
alias grs='git restore'
alias grset='git remote set-url'
alias grss='git restore --source'
alias grst='git restore --staged'
alias grt='cd "$(git rev-parse --show-toplevel || echo .)"'
alias gru='git reset --'
alias grup='git remote update'
alias grv='git remote -v'
alias gsb='git status -sb'
alias gsd='git svn dcommit'
alias gsh='git show'
alias gsi='git submodule init'
alias gsps='git show --pretty=short --show-signature'
alias gsr='git svn rebase'
alias gss='git status -s'
alias gst='git status'
alias gsta='git stash push'
alias gstaa='git stash apply'
alias gstall='git stash --all'
alias gstat='git status'
alias gstc='git stash clear'
alias gstd='git stash drop'
alias gstl='git stash list'
alias gstp='git stash pop'
alias gsts='git stash show --text'
alias gstu='gsta --include-untracked'
alias gsu='git submodule update'
alias gsw='git switch'
alias gswc='git switch -c'
alias gswd='git switch $(git_develop_branch)'
alias gswm='git switch $(git_main_branch)'
alias gtl='gtl(){ git tag --sort=-v:refname -n -l "${1}*" }; noglob gtl'
alias gts='git tag -s'
alias gtv='git tag | sort -V'
alias gunignore='git update-index --no-assume-unchanged'
alias gunwip='git log -n 1 | grep -q -c "\-\-wip\-\-" && git reset HEAD~1'
alias gup='git pull --rebase'
alias gupa='git pull --rebase --autostash'
alias gupav='git pull --rebase --autostash -v'
alias gupv='git pull --rebase -v'
alias gwch='git whatchanged -p --abbrev-commit --pretty=medium'
alias gwip='git add -A; git rm $(git ls-files --deleted) 2> /dev/null; git commit --no-verify --no-gpg-sign -m "--wip-- [skip ci]"'
alias history=omz_history
alias l='ls -lah'
alias la='ls -lAh'
alias ll='ls -FglAhp'
alias lmount='mount | column -t'
alias ls='ls --color=tty'
alias lsa='ls -lah'
alias md='mkdir -p'
alias mem5='ps auxf | sort -nr -k 4 | head -5'
alias rd=rmdir
alias speedtest='curl -s https://raw.githubusercontent.com/sivel/speedtest-cli/master/speedtest.py | python3 -'
alias which-command=whence
alias ..q="exit"
alias speedtest='curl -s https://raw.githubusercontent.com/sivel/speedtest-cli/master/speedtest.py | python3 -'
alias mem5="ps auxf | sort -nr -k 4 | head -5"
alias cpu5="ps auxf | sort -nr -k 3 | head -5"
alias extip="curl icanhazip.com"
alias lmount="mount | column -t"
alias e.="explorer.exe . || true"
alias c.="code . > /dev/null"
alias ports='netstat -tulanp'
# stop after sending count ECHO_REQUEST packets
alias ping='ping -c 5'
# do not wait interval 1 second, go fast
alias fastping='ping -c 100 -s.2'
# replace mac with your actual server mac address
alias wakeupnas01='/usr/bin/wakeonlan 00:11:32:11:15:FC'
alias wakeupnas02='/usr/bin/wakeonlan 00:11:32:11:15:FD'
alias wakeupnas03='/usr/bin/wakeonlan 00:11:32:11:15:FE'
# shortcut for iptables and pass it via sudo
alias ipt='sudo /sbin/iptables'
# display all rules
alias iptlist='sudo /sbin/iptables -L -n -v --line-numbers'
alias iptlistin='sudo /sbin/iptables -L INPUT -n -v --line-numbers'
alias iptlistout='sudo /sbin/iptables -L OUTPUT -n -v --line-numbers'
alias iptlistfw='sudo /sbin/iptables -L FORWARD -n -v --line-numbers'
alias firewall=iptlist
# get web server headers
alias header='curl -I'
# find out if remote server supports gzip / mod_deflate or not
alias headerc='curl -I --compress'
# do not delete / or prompt if deleting more than 3 files at a time
alias rm='rm -I --preserve-root'
# confirmation
alias mv='mv -i'
alias cp='cp -i'
alias ln='ln -i'
# Parenting changing perms on /
alias chown='chown --preserve-root'
alias chmod='chmod --preserve-root'
alias chgrp='chgrp --preserve-root'
# distro specific - Debian / Ubuntu install with apt-get
alias apt-get="sudo apt-get"
alias updatey="sudo apt-get --yes"
# update on one command
alias update='sudo apt-get update && sudo apt-get upgrade'
# become root
alias root='sudo -i'
alias su='sudo -i'
# reboot / halt / poweroff
alias reboot='sudo /sbin/reboot'
alias poweroff='sudo /sbin/poweroff'
alias halt='sudo /sbin/halt'
alias shutdown='sudo /sbin/shutdown'
# also pass it via sudo so whoever is admin can reload it without calling you
alias nginxreload='sudo /usr/local/nginx/sbin/nginx -s reload'
alias nginxtest='sudo /usr/local/nginx/sbin/nginx -t'
alias lightyload='sudo /etc/init.d/lighttpd reload'
alias lightytest='sudo /usr/sbin/lighttpd -f /etc/lighttpd/lighttpd.conf -t'
alias httpdreload='sudo /usr/sbin/apachectl -k graceful'
alias httpdtest='sudo /usr/sbin/apachectl -t && /usr/sbin/apachectl -t -D DUMP_VHOSTS'
# backup scripts
alias backup='sudo /home/scripts/admin/scripts/backup/wrapper.backup.sh --type local --taget /raid1/backups'
alias nasbackup='sudo /home/scripts/admin/scripts/backup/wrapper.backup.sh --type nas --target nas01'
alias s3backup='sudo /home/scripts/admin/scripts/backup/wrapper.backup.sh --type nas --target nas01 --auth /home/scripts/admin/.authdata/amazon.keys'
alias rsnapshothourly='sudo /home/scripts/admin/scripts/backup/wrapper.rsnapshot.sh --type remote --target nas03 --auth /home/scripts/admin/.authdata/ssh.keys --config /home/scripts/admin/scripts/backup/config/adsl.conf'
alias rsnapshotdaily='sudo /home/scripts/admin/scripts/backup/wrapper.rsnapshot.sh --type remote --target nas03 --auth /home/scripts/admin/.authdata/ssh.keys --config /home/scripts/admin/scripts/backup/config/adsl.conf'
alias rsnapshotweekly='sudo /home/scripts/admin/scripts/backup/wrapper.rsnapshot.sh --type remote --target nas03 --auth /home/scripts/admin/.authdata/ssh.keys --config /home/scripts/admin/scripts/backup/config/adsl.conf'
alias rsnapshotmonthly='sudo /home/scripts/admin/scripts/backup/wrapper.rsnapshot.sh --type remote --target nas03 --auth /home/scripts/admin/.authdata/ssh.keys --config /home/scripts/admin/scripts/backup/config/adsl.conf'
alias amazonbackup=s3backup
# all of our servers eth1 is connected to the Internets via vlan / router etc
alias dnstop='dnstop -l 5 eth1'
alias vnstat='vnstat -i eth1'
alias iftop='iftop -i eth1'
alias tcpdump='tcpdump -i eth1'
alias ethtool='ethtool eth1'
# work on wlan0 by default
# only useful for laptop as all servers are without wireless interface
alias iwconfig='iwconfig wlan0'
## pass options to free
alias meminfo='free -m -l -t'
## get top process eating memory
alias psmem='ps auxf | sort -nr -k 4'
alias psmem10='ps auxf | sort -nr -k 4 | head -10'
# get top process eating cpu
alias pscpu='ps auxf | sort -nr -k 3'
alias pscpu10='ps auxf | sort -nr -k 3 | head -10'
# get server cpu info
alias cpuinfo='lscpu'
# older system use /proc/cpuinfo
alias cpuinfo='less /proc/cpuinfo'
# get GPU ram on desktop / laptop
alias gpumeminfo='grep -i --color memory /var/log/Xorg.0.log'
# Reboot my home Linksys WAG160N / WAG54 / WAG320 / WAG120N Router / Gateway from *nix.
alias rebootlinksys="curl -u 'admin:my-super-password' 'http://192.168.1.2/setup.cgi?todo=reboot'"
# Reboot tomato based Asus NT16 wireless bridge
alias reboottomato="ssh admin@192.168.1.1 /sbin/reboot"
# this ones saved by butt so many times
alias wget='wget -c'
alias ff4='/opt/firefox4/firefox'
alias ff13='/opt/firefox13/firefox'
alias chrome='/opt/google/chrome/chrome'
alias opera='/opt/opera/opera'
alias ff=ff13
alias browser=chrome
# set some other defaults
alias df='df -H'
alias du='du -ch'
# top is atop, just like vi is vim
alias top='atop'
# nfsrestart - must be root
# refresh nfs mount / cache etc for Apache
alias nfsrestart='sync && sleep 2 && /etc/init.d/httpd stop && umount netapp2:/exports/http && sleep 2 && mount -o rw,sync,rsize=32768,wsize=32768,intr,hard,proto=tcp,fsc natapp2:/exports /http/var/www/html && /etc/init.d/httpd start'
# memcached
alias mcdstats='/usr/bin/memcached-tool 10.10.27.11:11211 stats'
alias mcdshow='/usr/bin/memcached-tool 10.10.27.11:11211 display'
alias flushmcd='echo "flush_all" | nc 10.10.27.11 11211'
alias ipe='curl ipinfo.io/ip'
alias ipi='ipconfig getifaddr en0'
3.2 Functions and User Configurations
CLICK TO EXPAND
# if user is not root, pass all commands via sudo
if [ $UID -ne 0 ]; then
alias reboot='sudo reboot'
alias update='sudo apt-get upgrade'
fi
# Get os name via uname
_myos="$(uname)"
# add alias as per os using $_myos
case $_myos in
Linux) alias foo='/path/to/linux/bin/foo';;
FreeBSD|OpenBSD) alias foo='/path/to/bsd/bin/foo' ;;
SunOS) alias foo='/path/to/sunos/bin/foo' ;;
*) ;;
esac
gcomm() {
git commit -am "$1 @ $(date)"
}
weather() {
clear
curl wttr.in/$1
}
cht () {
curl cheat.sh/$1
}
find_ip () {
IP=$1
MASK=$2
echo $IP $MASK
sudo nmap -PR $IP/$MASK -sn; arp -a | grep -v 'incomplete'
}
# coloring and stuff
export HISTSIZE=10000
export PATH=~/bin:$PATH
# set colors for LS_COLORS
eval `dircolors ~/.dircolors`
# hide the user and computer name in our prompt
DEFAULT_USER=$USER
# Function to delegate to Windows to open each of its arguments
start() {
for file in "$@"
do
cmd.exe /C "$file"
done
}
more here soon