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Ubuntu Terminal Cheatsheet

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Ubuntu Cheatsheet

This covers a wide assortment of quick references for the terminal/command-line. Additionally, near the bottom are more items for GUI and Troubleshooting.

Table of Contents

Common Commands


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| Command | Description | |----------------|--------------------------------------------------------------------| | :q | exits: MAN pages, VIM | | clear | dlears the terminal | | date | current datetime | | echo | output to terminal | | echo -e | output with variables and escape characters. | | env | See environment variables | | hostname | See your hostname | | locate crontab | I like mlocate more | | man ls | manual to give you a list of all command arguments for any command | | whatis ls | tells you about the command | | whereis bash | find absolute location of bash | | which python | location of a program |

Apt


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Apt (Or Aptitude) is the package manager for Ubuntu to manage packages.

There are some alternatives worth noting such as AppImage files and Snap packages, but that is out of scope here.

Tip: You can use the

-y
flag in any apt command to skip the
[Y/n]
dialog.

Apt Install

You need super user permissions, or

sudo
before the command.

To install packages, let's use an example such as Ruby which should have a list of items.

@note: means press the tab key

sudo apt install rub
# You should see a list of ruby installables.
# If it's a long list you can type this is exit:
:q
sudo apt install ruby2.3

TIP: I like to add to my

~/.bashrc
file an alias for this as follows:
alias apt=sudo apt

Apt Update

Update will get the latest versions of all repositories (and custom ones you add in the future) and allow you to install newer versions.

  • This lists are in:
    /etc/apt/sources.list.d/
apt update

Apt Upgrade

This will upgrade packages that have newer versions.

apt upgrade
# or, auto accept
apt upgrade -y

Apt Remove

Removing a package is just as simple.

apt remove someprogram
# or, auto accept
apt remove someprogram -y

However, this will not remove configuration files, so if you were to re-install it they would be preserved.

You may also run the following:

apt purge someprogram

Apt Lock Error

If you get an error such as

Unable to lock the administration directory (/var/lib/dpkg/) is another process
, follow these steps:
  • When you haven't booted in a while, be patient as this is one of the first things Ubuntu might do based on schedule. ~5 mins
  • Ensure another user is not running apt by typing:
    who
  • See if this has many operation running:
    ps aux | grep apt
    (Should return one line, which has no results and just the command you typed)
  • If you need to, delete the lock and archive files:
    • rm /var/lib/apt/lists/lock
    • rm /var/cache/apt/archives/lock
    • dpkg --configure -a
  • If the above does not work. Reboot the OS.

File Manager

  • The default file manager is
    nautilus
    .
  • Access From terminaal:
    nautilus .
  • Otherwise press SUPER and type
    files
    to get to it.
    • Set a Hotkey: Settings, CTRL+F, search for
      keyboard
      or
      shortcut
      .
    • Change
      Home Folder
      to a hotkey of your choice, I prefer SUPER + E since I came from Windows.

Listing and Navigating


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| Command | Description | |-------------|-------------------------------------------------| | cd .. | go down a directory | | cd / | go to lowest level | | cd /var/www | go to absolute path | | cd ~ | go to logged in user's home | | ls | list files | | ls -la | list all files, ~~permissions~~, and hidden too | | pwd | print working directory |

Manage Files and Folders

| Command | Description | |-------------------|----------------------------------------------| | cp -R

| copy directory from location to new location | | cp | copy file from location to new | location | | mkdir | create a directory | | mv | move directory from location | to new location | | mv | move file from location to new | location | | rm -rf | remove a directory with | contents | | rmdir | remove an empty directory | | touch | create an empty file |

Reading Files

| Command | Description | |-------------------|---------------------------| | cat | read entire file | | head | read top of a file | | head -n 20 | read top of file 20 lines | | tail | read bottom of a file | | tail -f | stream file as it's updated, | eg: an error log | | tail -n 20 | read bottom of file 20 lines |

Users


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| Command | Description | |--------------------------------------------|---------------------------------| | passwd | change logged in users password | | su - username | switch users | | sudo su | switch to root | | useradd -m -s /bin/bash username | Create User | | usermod -a -G existinggroup existinguser | Add User to Group | | who | show all logged in users | | whoami | show which user you are |

Groups


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Do not delete groups you don't know what they are used for, that's dangerous!

| Command | Description | |---------------|-----------------------------------------| | groups | see what groups current user belongs to | | groupadd name | create a group | | groupadd -g 900 name |create a group with | custom GroupID aka gid| ||| |groupdel name |delete a group| |useradd |add current user to a |group| |usermod -aG |append any user to an |additional group| ||| |cat /etc/group | list all groups| |cut -d: -f1 /etc/group | list all groups, cleaner|

Permissions


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There are two ways to manage permissions, one is by text the other is by an octal value.

Easy Permissions

; Change Mode
; Options: (O)wner (U)sers (G)roup or (A)ll
; File:    Owner: rwx, Group: rwx, User: rwx
; Misc:    Besides rwx there is:
;          s = setuid of owner for old/new files

; Single File read/write permissions chmod g+rw file chmod og+rw file.txt

; Change Ownership chown user:group files_or_folder chgrp group files_or_folder

; Recursively: chown -R user:group files_or_folder chgrp -R group files_or_folder chmod -R og+rw files_or_folder chmod -R g+s files_or_folder

Preserve Group Permissions

A fantastic way to structure your users is within groups. A common example would be your

www-data
group. If I have a user
jesse
, I can add him with
sudo usermod -aG www-data jesse
.

After adding any users I would like, I want to have a folder where all the members of the

www-data
group can read/write a folder. If they are using git, I also want the permissions to stay the same, meaning if they pull the permissions will not change.

To accomplish this, here is an example:

sudo chown -R deploy:www-data /var/www
sudo chmod -R g+rws /var/www

The

g+s
sets the file(s)/folder(s) a gid (
setgid
) so that new files will inherit the original group!

Octal Permissions

You may have seen this a lot, you can use octal or decimal (begins with a 0) to do the same thing.

Permissions:
0 = None
1 = Execute (e)
2 = Write (w)
4 = Read (r)
  • There are 3 Permission types (Read, Write, Execute), or 4 if you count "None".
  • There are 3 Sets: Owner/User/Group (In that order)
  • So if you did
    chmod 700 file.txt
    it would allow the user to Read, Write and Execute
    • Because
      7
      is the total of
      4 + 2 + 1

Octal Examples

chmod 600 file.txt – Owner Read, Write
chmod 660 file.txt – Owner Read, Write; User Read, Write
chmod 770 file.txt – Owner Read, Write, Execute
chmod 770 file.txt – Owner Read, Write, Execute; User Read, Write, Execute
chmod 666 file.txt – All Read, Write
chmod 777 file.txt – All Read, Write, Execute

OS Details


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Get fundamental information about your OS with the following commands, you may have to run them as

sudo
, eg:
sudo lsb_release -a
.

Operating System

lsb_release
lsb_release -a
lsb_release -as     # Short Information
lsb_release --help

CPU Info

nproc               # How many Processing Units
cpuid               # Must install cpuid from terminal
cat /proc/cpuinfo   # Lots of info

Usage Info

free -h             # Human readable, or do --help for options
vmstat -s
cat /proc/meminfo   # Lots of info

Disk Space

df
df -B MB    (In Megabtyes, KB for Kilobytes, GB for Gigabytes)

System Processes

top
htop  # If you installed it

IP Address

Your IP is after

inet addr
. If you are connect via ethernet it's under
eth0 (Ethernet)
otherwise, wirelessly it is likely under
wlan0 (Wireless LAN)
.
ifconfig
ip
ip addr show
ip addr show wlan
ip addr show eth0

GUI Processes

gnome-system-monitor

CLI Processes

top
htop     (My favorite, sudo apt-get install htop)
nmon

List all Keybindings


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gsettings list-recursively  org.gnome.desktop.wm.keybindings | sort | more

See Keypressed

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xev

; Or for a lot of details:

xev | grep KeyPress

Kernal


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The Kernal is the lowest level item that ties everything together from hardware to software. Without a kernal you cannot do anything on linux.

Remove Old Kernals

See What version you are currently using

sudo uname -a

See all the Kernals on the OS

sudo dpkg --get-selections | grep linux

The BYOBU is quite nice

sudo apt install byobu
sudo purge-old-kernels

OS Shutdown


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shutdown
reboot
shutdown -h now
shutdown -h +10     (shutdown 10 mins)
shutdown -r now     (reboot now)

Crontab


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crontab -e              (edit crontab for current user)
crontab -l              (list crontab for other user)
crontab -u jesse -l     (see crontabs for specific user)

Services


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Service Commands

Use the service command (Requires sudo)

service ssh status      (service status)
service --status-all    (all services status)

Almost every service has the following commands, some may have more like apache

graceful-restart
:
service servicename start
service servicename stop
service servicename restart
service servicename status
service servicename force-reload

Autostart

Add Service links:

sudo update-rc.d servicename defaults

Whether you get a warning if they already exist or not, enable it now:

sudo update-rc.d servicename enable

Remove Autostart

Pass the Force flag

sudo update-rc.d -f servicename remove

Autostart Daemons

There is are several startup popular daemons: - CentOS uses SystemV - Ubuntu 14 uses Upstart - Ubuntu 14.10+ uses SystemD (15, 16, 17..)

Focus on SystemD.

SystemD Commands

This would only apply to Ubuntu 14.10+, otherwise you would use Upstart.

systemctl     

System State


(Back to Top) ``` uname -a (get linux info)

top (See running processes/system status, I suggest installing

htop
) top -u www-data htop -u www-data

df (display disk space in bytes, default) df -h (display disk space human readable) df -Th (display disk space with partitions)

free (see memory used) free -g (in gigabytes) ```

Processes


(Back to Top) ``` ps -ef | more (current running processes) ps -efH | more (current running processes in a tree)

ps -ef | grep vim (find vim process id) kill -9 (no brackets) ```

Bash


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Bash is my shell of choice, which is why I have a

.bashrc
file.

Bash Paths

Executables and commands are automatically in the path, see your path with:

echo $PATH

Add to Path

# I suggest editing your ~/.profile

vim ~/.profile if [ -d "/path/to/your/bin" ] ; then PATH="$PATH:/path/to/your/bin" fi

Note: Order of Linux Reading files: ~/.bashprofile, ~/.bashlogin, and ~/.profile, so don't try to use a ~/.profile variable within ~/.bash_profile

Bash Completions

The locations for bash completio0ns can be found at:

cd /usr/share/bash-completion/completions.d/
cd /etc/bash_completions.d/

Fix Broken Bash Completions

sudo apt-get install --reinstall bash-completion

Log Script from Bash

At the top of your file, find the executable you are using one of these, eg:

which bash     # /usr/bin/bash
which python   # /usr/bin/python
which php      # /usr/bin/php

At the top of your shebang for the executable file add:

#!/bin/bash
#!/usr/bin/php
#!/usr/bin/python

make sure to

+x
it:
chmod +x app.sh
chmod +x app.php
chmod +x app.py

You can then run the script via Bash:

/scripts/app.sh >> /scripts/output.log 2>&1
/scripts/app.php >> /scripts/output.log 2>&1
/scripts/app.py >> /scripts/output.log 2>&1

You could even crontab it the same way:

*/10 * * * * app.php >> /output.log 2>&1
*/10 * * * * app.py >> /output.log 2>&1

Finding Files


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Generally the following arguments are as follows: -

-type f
file -
-type d
directory -
-iname
case insensistive (book.txt would the same as BOOK.TXT) -
*
is a wildcard to find anything, usually you put it at the start or end of a filename.
find . -name tecmint.txt
find /home -name tecmint.txt
find /home -iname tecmint.txt                        (case ignore)
find / -type d -name Tecmint                         (directory)
find . -type f -perm 0777 -print (with perms)
find / -type f ! -perm 777 (find without)
find . -type f -name "tecmint.txt" -exec rm -f {} \; (find and remove a file)
find . -type f -name "*.txt" -exec rm -f {} \;       (find and remove multiple)
find /tmp -type f -empty                             (Find empty files)
find /tmp -type d -empty                             (find empty directories)
find / -size +50M -size -100M (findby swize)

Find in Files (GREP)


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GREP means: Global Regular Expression Pattern (or Parser)

Some common GREP flags: -

-r
is Recursive -
-n
is Line Number -
-w
Match the whole word -
-l
is lowercase only -
-c
supresses normal output and counts number of matching lines
grep -rn /path - "pattern_or_string"

; Output results to File grep -rnw /path - "pattern_or_string" > output.txt

Look only in certain filetypes

; notice I used a regex ^ starts with, you can use a string or regex
grep --include=*.sh '^mysql' ./

More Examples:

grep "hello" file.txt (if in file)
grep "hello" files*  (if in many files)
grep -i "hello"  file.txt  (case insesitive)
grep -iw "is" file.txt (get full words, case insensitive)
grep "regex" file.txt

Pipe Grep

php -i | grep ini

Reading Files


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Without having to open a file you can simply read a part of it without

nano
,
pico,
vi
, or
vim
:
cat file.txt            (view file contents)
tail file.txt           (view end of file contents)
tail -n20 file.txt      (view top 20 lines)
tail -f filetxt         (follow a filename keep updating)
head file.txt           (view top of file contents)
head -n20 file.txt      (view top 20 lines)
`

Downloading Files


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Using Wget

wget http://file.com/something.txt                (Download a file locally)
wget -O newname.txt http://file.com/something.txt (Download file locally w/new name)

You can also use

SCP
, yet the above are easier for non-SSH connections.

Using cURL

curl -O http://file.com/something.txt               (Download a file locally)
curl -o newname.txt http://file.com/something.txt   (Download file locally w/new name)
curl -O http://url_1 -O http://url_2                (Download multiple files)

Compressing and Uncompressing Files


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To Compress a file you can use a variety of tools. You can type

man gzip
to see the full manual and line of commands, and use
esc
+
:x
and
ENTER
to exit from the Manual (It usually uses the Vi editor).

Most often in the Linux word you use and create

*.tar.gz
files, it has the most options. Whatever you prefer is up to you.

What the flags often stand for: -

-c
is create -
-f
is file -
-k
is for Keep -
gzip
&
bzip2
will remove the original file once compressed - Or they will remove the
.gz
when decompressing is done -
-r
is recursive (for gzip and zip) -
-v
is verbose (show details of what's happening) -
-z
is for tar to gzip as well -
--exclude='file'
is for tar (+gz if needed) to exclude certain files)

Compressing Files

Note: You can compress more than one file at a time eg:

bzip2 file1.txt file2.txt file3.txt
gzip -vk file.txt                   (Creates file.txt.gz)
bzip2 file.txt                      (Creates  file.txt.bz2)
tar -cvf file.tar file.txt          (Creates tar)
tar -czvf file.tar.gz file.txt      (Creates tar.gz)
zip filename.zip file.txt           (Creates filename.zip)
zip -r folder.zip path/to/folder    (Creates  folder.txt.bz2)

Include/Exclude a few files: ``` ; Exclude certain files tar -czvf file.tar.gz / --exclude='*.jpg' --exclude='bigfile.sql'

; Include one file type tar -czvf file.tar.gz /*.sh

; Include multiple files types tar -czvf file.tar.gz

find  | grep '.sh\|.py'
```

Decompressing Files

To Uncompress we use similar commands for most of them

gunzip -dvk file.txt.gz
gzip -dvk file.txt.gz       (Same as above)
bzip2 -d file.txt.bz2
tar -xvf file.tar
tar -zxvf file.tar.gz
unzip test.zip

SCP


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Download from server to local

scp [email protected]:/path/to/file.txt file.txt

Upload from local to server

scp file.txt [email protected]:/path/to/file.txt

SSH


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Connecting to a server

ssh [email protected]  (default port is 22)
ssh [email protected] -p 8000 (connect to specific port)
ssh [email protected] -i ~/.ssh/rsa_key.pub (connect with ssh key)

.SSH Permissions

These are safe permissions to use for SSH ``` chmod 700 ~/.ssh chmod 644 ~/.ssh/idrsa.pub chmod 600 ~/.ssh/idrsa

Put your pubkeys (one per line) for SSH login

chmod 600 ~/.ssh/authorized_keys ```

Using the Config

You can also create a

~/.ssh/config
file and store entries such as: ``` Host aws Hostname ec2-50-50-130-50.compute-1.amazonaws.com Port 22 Identityfile ~/.ssh/id_rsa User myusername

Host my-vps Hostname 50.50.130.50 Port 22 User root ```

You can then simply type:

ssh aws
ssh my-vps

SSH to PEM

Sometimes you may need a

PEM
format SSH Key. You can easily add this alongside your other SSH keys.
openssl rsa -in ~/.ssh/keyname_rsa -outform pem > keyname_rsa.pem
chmod 700 keyname_rsa.pem

Firewall


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A firewall prevents unauthorized access to your machine, you should use

UFW
(Uncomplicated Firewall). You must always run this with
sudo
. If you don't have UFW installed, run:
sudo apt-get install ufw

UFW Status

To see the Firewall Status run one of these:

sudo ufw status
sudo ufw status verbose

UFW Enable/Disable

sudo ufw enable
sudo ufw disable

UFW Example Customization

Please do not do this unless you know what you are doing.

You could start out with blocking all incoming connections.

sudo ufw default deny incoming
sudo ufw default allow outgoing

Then we allow only what we want

sudo ufw allow ssh
sudo ufw allow http
sudo ufw allow https
sudo ufw allow ftp

These are the same as:

sudo ufw allow 22   # same as ssh
sudo ufw allow 80   # same as http
sudo ufw allow 443  # same as https

UFW More Options

If SSH was on port

3333
rather than the default
22
you would do:
sudo ufw allow 3333/tcp

Some more options:

sudo ufw allow 25 # SMTP
sudo ufw allow 110 # POP3
sudo ufw allow 995 # POP3S
sudo ufw allow 143 # IMAP
sudo ufw allow 993 # IMAPS
sudo ufw allow 3306 # MySQL
sudo ufw allow 5432 # Postgres
sudo ufw allow from 192.168.255.255 # Custom IP Address

UFW Deleting Rules

Easily delete named rules

sudo ufw delete allow ssh

Delete rules that are numbered

sudo ufw status numbered
sudo ufw delete [number]

UFW Reset Rules

sudo ufw reset

Regex


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Regex stands for Regular Expression. It's used for locating or replacing files or strings of text. It is used all the time. These can be used in Linux itself and programming languages.

; Symbolism
; ------------------
()          (captures groups)
[]          (set)
{}          (quantifier)
?           (optional, matches 0 or 1 character)
*           (matches 0 or more characters)
.           (match any character)
+           (match one or more character)
\           (escape character)
!           (false, is not)
^           (starts with)
$           (ends with)
|           (or statement, eg: (jesse|dan|jenkins) )

; Basic Primer ; ------------------ \w (word) \W (non-word) \s (whitespace) \S (non-whitespace) \d (digit) \D (non-digit) [ab] (character set) [^ab] (negated set) [a-m] (range) (hello) (group) (hello)+ (group, more than once)

; Groups ; ------------------ (hi) (gets all "hi" occurances) (^hi) (gets all text starting with "hi") (es$) (gets all text ending with "es") (hi)\1 (gets the first occurance of "hi")

; Flags ; ------------------ /i (case insensitive) /g (global) /m (multiline)

; Escaped Characters ; ------------------ ; Since characters such as ".", "+", etc are actual Regex pattern makers, if you ; need to check your content for the literal item you must escape them. . (matches . character) + (matches + character) ? (matches ? character) * (matches * character) ^ (matches ^ character) $ (matches $ character) [ (matches [ character) ( (matches ( character)

\t (matches tab character) \n (matches newline) \r (matches return carriage) \0 (matches NULL character) \ (matches \ character) / (matches / character)

Regex Examples

Put Examples here, like phones, names, etc..

MySQL


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  • -u
    is for User (default: root)
  • -p
    is for Password
  • -p password
    is for password which skips the prompt (not recommended)
  • -h
    is for host (default: localhost)
  • -port or -P
    is for a port, default is 3306
  • -f
    will force SQL import and skips errors
  • -v
    will display verbose output
  • In the
    mysql>
    terminal you can get clean data by doing
    \g
    :
    • mysql> SELECT * FROM users LIMIT 10\g";

Connecting

mysql -u root -p (username, password prompt)
mysql -u root -p -h localhost (username, password prompt, host)
mysql -u root -p password -h localhost -P 3306

; AWS Example (AWS Defaults to 3306 as most MySQL connections do) mysql -u username -p password -h myinstance.123456789012.us-east-1.rds.amazonaws.com

Exporting Database to SQL

You can dump a single database easily:

mysqldump -u root -p DATABASE_NAME > file.sql

Or Dump all databases on your MySQL server with the

--all-databases
flag:
mysqldump -u root -p --all-databases > file.sql

Importing SQL Files

You can do this through the shell only, or MySQL, first is the shell:

mysql -u root DATABASE_NAME < path/to/file.sql

To continue when there are MySQL Errors use -f or --force below:

mysql -u root DATABASE_NAME < path/to/file.sql --force

To use a password, just pass in the -p flag and type it in after running:

mysql -u root -p DATABASE_NAME < path/to/file.sql --force

Second, you can do it through MySQL once you connect:

mysql> use DATABASE_NAME;
mysql> source path/to/file.sql;

Exporting Compressed Database

This will save a lot of space in this one liner:

mysqldump -u root -p DATABASE_NAME | tar -cvzf > output.sql.tar.gz
mysqldump -u root -p DATABASE_NAME | gzip -v > output.sql.gz

Importing Compressed Database

Here is how you can import with the one liner:

mysql -u root -p DATABASE_NAME | tar -xzOf output.sql.tar.gz
mysql -u root -p DATABASE_NAME | gunzip < output.sql.gz

Get Database Encoding

USE DATABASE_NAME;
SELECT @@collation_database;

Get Table Encoding

SELECT default_character_set_name FROM information_schema.SCHEMATA
WHERE schema_name = "TABLE_NAME";

Get Column Encoding

Look at the collation table. Numeric fields won't have a collation.

SHOW FULL COLUMNS FROM TABLE_NAME

Fix Broken Characters

First, try this query without affecting anything to see:

SELECT CONVERT(BINARY CONVERT('We’re Here!' using latin1) using utf8);
That should fix the encoding problem.

To update a column:

UPDATE TABLE_NAME SET COLUMN_NAME = CONVERT(BINARY CONVERT(COLUMN_NAME using latin1) USING utf8);

Git


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Populate a Repository

You have to first create a repostory, through BitBucket, GitHub, GitLab, etc.

git init
touch README.md
git remote add origin [email protected]/username/yourrepo.git
git add .
git commit -m "Starting with one file"
git push origin master

Add or Remove Files

git add file.txt
git rm file.txt

Ignoring files

Create a

.gitignore
file, and place something like this in it:
.tmp
.py[co]
.cache
.DS_Store

Create a Branch

Branches are used like when you don't want to ruin a main branch with working code.

git checkout -b develop
git push origin develop

Switch Branches

git checkout master
git checkout develop

Pull One File From Another Branch

If you were on your

master
branch and only wanted to pull a single file from
develop
branch, you can do this: ``` ; Make sure you're on the branch you want to pull into git checkout master

; Pull a single file into master from develop git checkout develop -- relative/path.txt

; Continue by comitting and pushing to master ```

Create a Tag

Tags create a snapshots of current code, you may name it as a version such as

1.0.1
and it produces a
tar.gz
and
zip
format for downloads.
git tag -a 1.0
git tag -a 1.0 -m "Optional Message"
git push --tags

Remove a Tag

This will remove a tag from the Git host.

git tag -d 1.0
git push origin :refs/tags/1.0

Clone a Respository

git clone [email protected]/username:your_repo.git

Clone into current directory

git clone [email protected]/username:your_repo.git .

Current Status

git status

Commit Log and Show

To see log data and more details use the short or long commit ID.

git log
git show eb7c86a5fbdc6c64df608f4c143c2718a100983b

Reset Hard

This will reset your repository to the last revision and undo everything, use with caution.

git reset --hard HEAD

Prune

Removes cached items no longer read by git

git prune

Docker


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To install visit https://docs.docker.com/engine/installation/linux/ubuntulinux/ - Images: (Blueprints of an application) - Image BASE: No parent Image (An OS) - Image CHILD: Builds on a Base Image (Eg: Webserver, MySQL) - Containers: Created from an IMAGE and run an application. - Docker Daemon: Background service that builds, runs, and does everything. - Docker Client: Allows us to interact with the Docker Daemon. - Docker Hub: A registry of images (Like: npmjs, pip, packagist, bower)

Docker Compose

This is a great utility that makes managing docker easier from a

docker-compose.yml
file, you should install this after playing around with the below options. See: https://docs.docker.com/engine/installation/linux/ubuntulinux/
docker-compose up
open http://localhost:3000

Test Box Run

This is a sample box to test once you installed docker

dock pull busybox
docker images
docker run busybox "Hi from the box"

See Running Containers

docker ps (running containers)
docker ps -a (see all containers that ran)

Run Container Interactively

This allows you to get inside the container

docker run -it busybox sh (interactive)

Remove Container

Removes a CONTAINER, not an IMAGE

docker ps -a
docker rm 

Bulk Remove Containers

You can remove containers based on their status in bulk, eg:

docker rm $(docker ps -a -q -f status=exited)
docker rm $(docker ps -a -q -f status=created)

Webserver Test Image

This will download the IMAGE and run it if it doesn't exist

docker run prakhar1989/static-site

This doesn't expose ports for us to use, so we do the following:

docker run -d -P --name static-site prakhar1989/static-site
  • -d
    detaches terminal so we can run commands in our terminal
  • -P
    publishes all exposed ports to random ports

By doing the above command we are given random ports, eg:

  443/tcp -> 0.0.0.0:32768
  80/tcp -> 0.0.0.0:32769

Your ports may be different, you can use specific ports with a lowercase

-p
:
docker run -p 8888:80 prakhar1989/static-site

Stop Container

docker stop static-site

Get New Docker Image

This would be a docker BASE IMAGE

docker pull ubuntu:14.04

Create Docker Image

This is a flask Example using a Python-3 Base IMAGE

  • Create
    requirements.txt
    and just put
    flask
  • Create an
    app.py
  • Use the following sample code in
    app.py
    :
from flask import Flask
app = Flask(__name__)

@app.route('/') def hello_world(): return 'Hello, World!'

  • Create a docker file, title it
    Dockerfile
  • Enter the following
FROM python:3-onbuild
EXPOSE 5000
CMD ["python", "./app.py"]

Now build the image

docker build -t boyus .
docker images

Remove Docker Image

Get a list of images, then just delete by image id with

rmi
aka
remove image
:
docker images
docker rmi 

Pushing Images

You need a repository at docker.io to push this, or probably some private hosting.

docker push boyus

Installing GUI's


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Linux has a lot of GUI's and you are not limited to what you get. I'll list a few popular ones with the installation instructions in Ubuntu. You can have as many GUI options as you like, just change the default at the login screen.

Tip: After you install, logout and in the login menu or the top right you can select what GUI you want to login with. Whenever you install a new GUI you can select a Display Manager, I recommend using

lightdm
.

--

Unity

Unity Website

Installed in Ubuntu 12+ by Default (`ubuntu-desktop`)

XUbuntu

XUbuntu Website

; Install:
sudo apt-get install xubuntu-desktop

; Remove: sudo apt-get remove xubuntu-desktop

Cinnamon (Linux Mint)

Linux Mint Website

; Install:
sudo add-apt-repository ppa:moorkai/cinnamon
sudo apt-get update && sudo apt-get install cinnamon

; Remove sudo ppa-purge ppa:moorkai/cinnamon

GNOME

GNOME Website

This has been one of the all time most popular GUI's for Linux ever made, in particular the

gnome-classic
.
; Install:
sudo apt-get install ubuntu-gnome-desktop    (For legacy gnome use you can use gnome-shell, this install both)

; Remove: sudo apt-get remove ubuntu-gnome-desktop (Removes gnome-shell as well)

Gnome3 has been my favorite GUI due to how I can customize it. However, for unknown reasons I have issues running only Gnome3 in VMWare Workstation 11. It works fine as a complete install.

Noteworthy: Visit Gnome Shell Extensions to customize anything you want. Make sure to use Firefox.

KDE

KDE Website

This is a very popular GUI for people that are used to Windows Desktops.

; Install:
sudo add-apt-repository ppa:kubuntu-ppa/backports
sudo apt-get update && sudo apt-get dist-upgrade
sudo apt-get install kubuntu-desktop

; Remove: sudo apt-get remove kubuntu-desktop

LXQT

LXQT Website

; Install:
sudo apt-get install lxqt
; Remove:
sudo apt-get remove lxqt

Pantheon (ElementaryOS)

Elementary OS Website

For the best stability I use Elementary OS which is based off of Ubuntu.

; Install:
sudo add-apt-repository ppa:elementary-os/stable
sudo apt-get update
sudo apt-get install elementary-desktop

; Remove: sudo apt-get remove elementary-desktop

XFCE

XFCE Website

; Install:
sudo apt-get install xfce4

; Remove: sudo apt-get remove xfce4

Troubleshooting


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Sometimes the system has problems, seldmoly but I'll list things that helped me fix rare occasions.

Ubuntu Infinite Login

When you try to login to Ubuntu and it relogs you back into the login screen, this is an infinite loop. The only way I was able to fix it depsite all the guides was combining a few of these together for Ubuntu 16.04.

If you are using Gnome as I do, I would jump down to the Apt Auto Remove Problem in the list.

The first step is to login to a terminal.

CTRL + ALT + F1  (Or F3)

Next, Login as your user who must be able to run

sudo
.
  • Temp Folder Permissions
    • ls -ld /tmp
      should have these permission exactly as:
      drwxrwxrwt
    • The user:group must be
      root:root
      on
      /tmp
      .
    • To Fix:
      sudo chmod a+wt /tmp
  • Xauthority Ownership
    • ls -lta | grep .Xa
      should be owned by your user, for example
      jesse jesse
    • If it is
      root root
      or anything than your user/group it's wrong.
    • To Fix:
      sudo chown jesse:jesse .Xauthority
  • Xsession Errors
    • This is just to make sure there are no syntax errors for your reference:
    • To Check:
      cat ~/.xsession-errors
    • You don't need to do anything if there are syntax errors, we will move the file.
  • Try Moving XAuthority
    • Sometimes it's as easy to moving Xauthority so a new is generated at login.
    • To Fix:
      sudo ~/.Xauthority ~/.Xauthority.bkup
  • Try Reconfiguring LightDM
    • Fix:
      dpkg-reconfigure lightdm
      , then select lightdm in the menu
    • Lastly restart lightdm:
      sudo service lightdm restart
  • Apt Auto Remove Problem
    • I read that it's possible
      apt-autoremove
      may accidentally remove
      xubuntu-desktop
      ,
      ubuntu-desktop
      and LightDM reports no errors.
    • The
      ubuntu-desktop
      will load the Unity interface
    • The
      xubuntu-desktop
      will load a different interface I'm not familiar with.
    • To Fix:
      sudo apt-get install xubuntu-desktop ubuntu-desktop
    • If you are using Gnome, try following the post at OMGUbuntu
    • After the Above Try:
      sudo apt-get autoremove gnome-software && sudo apt-get install gnome-software
    • I was able to get Gnome-Classic working but not Gnome.
  • How to Ensure it Works
    • You might be able to login after one of the steps above if you don't reboot. However, to be certain, you want to reboot to ensure it is fixed, otherwise you'll be doing this over and over.

Linux Facts


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  • Linux Versions refers to The Kernel which ties the OS together.
  • Linux Distributions are the named Linux "Flavors" below.
    • Debian
    • Linux Mint (LMDE) forked from Debian
    • Ubuntu forked from Debian
      • Elementary OS forked from Ubuntu
      • Linux Mint forked from Ubuntu
      • Kubuntu forked from Ubuntu
    • Fedora
    • Red Hat Enterprise Linux (RHEL) forked from Fedora
      • CentOS forked from RHEL (Community Edition of RHEL)
    • Gentoo
  • ..And many others. Debian -> Ubuntu has been the most popular.

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