System administration
System administration
Initial setup (for Ubuntu distribution)
SSH keys
Create private/public SSH key file using 2048 bit encryption and with a comment. The command creates files under ~/.ssh folder.
$ ssh-keygen -b 2048 -C user@host.domain
SSH config for connection
The config file ~/.ssh/config stores information about various SSH connections, and allows the definition of hostname, username, ports, and other settings.
Host hostname1
HostName hostname1.domain.com
User username1
Port 1234
Adding a user to sudoers list
#includedir /etc/sudoers.d
should be at the end of /etc/sudoers file.
Create a file under this directory (i.e. localusers) and add entries.
jsmith ALL=(ALL) NOPASSWD:ALL
would allow a user to sudo without entering a password.jpocahontas ALL=(ALL) ALL
would force password entry
Run $ chmod 0440 filename
afterwards.
Enable color prompt
On Ubuntu distribution of GNU/Linux, you can uncomment force_color_prompt = yes line to use color prompts. The following is my personal favorite color configuration for the prompt.
PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u\[\033[01;30m\]@\[\033[00;36m\]\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ '
Enable byobu
$ byobu-enable
Update .vimrc
syntax on
set noexpandtab
set wrap
set tabstop=4
set shiftwidth=4
set smartindent
set autoindent
set encoding=utf-8 fileencodings=
set mouse=a
set fo=cqlro
set tags=tags,../tags,../../tags,../../../tags,../../../../tags,../../../../../tags,../../../../../../tags
color elflord
" set foldmethod=marker
set foldmethod=indent
set foldnestmax=15
set nofoldenable
set foldlevel=1
" filetype plugin on
imap <c-k> <esc>:r! zdump GMT <bar> tail -c29 <bar> xargs -0 date +"\%-m/\%-d/\%-Y \%-l:\%M:\%S \%p" -d<enter>$i<right>
" PHP documenter script bound to Control-P
autocmd FileType php inoremap <C-p> <ESC>:call PhpDocSingle()<CR>i
autocmd FileType php nnoremap <C-p> :call PhpDocSingle()<CR>
autocmd FileType php vnoremap <C-p> :call PhpDocRange()<CR>
Set up environment for web development
Install the LAMP stack
$ sudo apt-get install tasksel
$ sudo tasksel install lamp-server
Install git and other PHP related extensions
$ sudo apt-get install git php5-mcrypt php5-xdebug php5-intl
.gitconfig
[core]
editor = vim
excludesfile = /home/mhan/.gitignore_global
# autocrlf = input
# safecrlf = true
[color]
ui = always
[alias]
co = checkout
ci = commit
st = status
br = branch
df = difftool
hist = log --pretty=format:\"%C(yellow)%h %C(green)%ad %Creset| %s%C(red)%d %C(blue)[%an]\" --graph --date=short
histall = log --pretty=format:\"%C(yellow)%h %C(green)%ad %Creset| %s%C(red)%d %C(blue)[%an]\" --graph --date=short --all
hist10 = !git log --pretty=format:\"%C(yellow)%h %C(green)%ad %Creset| %s%C(red)%d %C(blue)[%an]\" --graph --date=short | head -n 10
hist10all = !git log --pretty=format:\"%C(yellow)%h %C(green)%ad %Creset| %s%C(red)%d %C(blue)[%an]\" --graph --date=short --all | head -n 10
type = cat-file -t
dump = cat-file -p
ignore = update-index --assume-unchanged
track = update-index --no-assume-unchanged
listignored = !git ls-files -v | grep -s ^'h ' | cut -b 1-2 --complement
[diff]
tool = vimdiff
[difftool]
prompt = false
[merge]
defaultToUpstream = true
Change default shell
$ chsh
Edit passwd files
$ sudo vipw
Resources
Check disk space usage
You can check the file space usage with the command du.
$ du -h
Check disk space left
df is for checking the amount of disk space used and available on file systems.
$ df -h
User Accounts
Groups
Add a new group
$ sudo addgroup webdev
Delete a group
$ sudo delgroup webdev
Add a user to a group
$ sudo adduser username groupname
Set a directory writable by a certain group
Make /srv/www folder readable/writable/executable by dev group
$ sudo setfacl -d -m g:dev:rwx /srv/www
Add a user account
$ sudo useradd -d /home/jsmith -m jsmith -G webdev
$ sudo passwd jsmith
Delete a user account
Force removal and delete files
$ sudo userdel -fr username
or
$ sudo deluser -remove-home username
Lock or unlock a user account
$ sudo passwd -l username
$ sudo passwd -u username
Adding sudoers
A file can be added for groups of users or specific users to /etc/sudoers.d/ directory. This line would make someone a sudoer with no password requirement.
jsmith ALL=(ALL) NOPASSWD:ALL
If you want the user to type a password.
jsmith ALL=(ALL:ALL) ALL
Samba
Reset password for Samba server
$ samba-tool user setpassword administrator
OpenSSL
Creating self-signed certificates (usually for SSL connection)
$ sudo a2enmod ssl
$ sudo service apache2 restart
$ sudo mkdir /etc/apache2/ssl
$ sudo openssl req -x509 -nodes -days 365 -newkey rsa:2048 -keyout /etc/apache2/ssl/apache.key -out /etc/apache2/ssl/apache.pem -outform PEM
Debian/Ubuntu-specific
Reconfigure console font
$ dpkg-reconfigure console-setup
Change time zone
$ dpkg-reconfigure tzdata