GNU/Linux – Page 2 – Alex Arriaga

alex-arriaga July 6, 2014

Some useful Git commands

GNU/Linux, Mac OSX, Operating Systems, Windows 1 Reply

Hi friends,

Today I would like to share you a list of Git commands that I consider really useful when we work with this great version control system. Enjoy it!

Configuring your Git

// Disable autocrlf to avoid warnings in command line
git config --global core.autocrlf false

1 2	// Disable autocrlf to avoid warnings in command line git config --global core.autocrlf false

// Set username and email (global)
git config --global user.name “My user name” 
git config --global user.email “my-email@awesome.com” 

// Display configuration
git config -l 

// Get some help :)
git contig -h

// Set username and email (global)

git config --global user.name “My user name”

git config --global user.email “my-email@awesome.com”

// Display configuration

git config -l

// Get some help :)

git contig -h

Managing Git repositories

Initializing a repo

git init

git init

Adding files for tracking or to the staging area

// Add all .txt files
git add *.txt

// Add all in the current directory
git add .

// Add a single file
git add README.md

// Add all .txt files

git add *.txt

// Add all in the current directory

git add .

// Add a single file

git add README.md

Resetting your files in the staging area to the working directory

git reset HEAD <file>
git reset HEAD -- <path/to/file>

// Examples
git reset HEAD index.html
git reset HEAD .

git reset HEAD <file>

git reset HEAD -- <path/to/file>

// Examples

git reset HEAD index.html

git reset HEAD .

Doing your changes persistent in the local repository

// Do a commit with all files in staging area
git commit -m "My custom message for this commit"

1 2	// Do a commit with all files in staging area git commit -m "My custom message for this commit"

Watching previos version of files

// Watch a version of a very specific file (using the commit ID)
git checkout YOUR_COMMIT_ID -- path/my_file.js

// Return to the version of that file in HEAD
git checkout HEAD -- path/my_file.js

// Watch a version of a very specific file (using the commit ID)

git checkout YOUR_COMMIT_ID -- path/my_file.js

// Return to the version of that file in HEAD

git checkout HEAD -- path/my_file.js

Watching logs

// Watch the log (details)
git log 

// Watch the log in one line per commit
git log --oneline 

// See two last commits
git log --oneline -2

// Show diff between files
git show

// Watch the log (details)

git log

// Watch the log in one line per commit

git log --oneline

// See two last commits

git log --oneline -2

// Show diff between files

git show

Merging a branch (my-branch) into other (master)

// Where do you want to merge?
git checkout master

// Which branch do you want to merge?
git merge my-branch

// Where do you want to merge?

git checkout master

// Which branch do you want to merge?

git merge my-branch

Restoring files

See the stored version of an specific file in a commit:

git checkout COMMIT_ID "path/to/the/file"

// Example
git checkout 6881326  "widgets/Awesome Widget/MyAwesomeWidget.dust.tpl.htm"

git checkout COMMIT_ID "path/to/the/file"

// Example

git checkout 6881326 "widgets/Awesome Widget/MyAwesomeWidget.dust.tpl.htm"

Working with branches

Creating, deleting and switching to a branch

// Get a list of branches in the repository
git branch

// Create a new branch
git branch my-branch

// Switch to a branch
git checkout my-branch

// A shorthand for two previous commands (create and switch)
git checkout -b other-branch 

// Delete a branch
git branch -d my-branch

// Get a list of branches in the repository

git branch

// Create a new branch

git branch my-branch

// Switch to a branch

git checkout my-branch

// A shorthand for two previous commands (create and switch)

git checkout -b other-branch

// Delete a branch

git branch -d my-branch

Working with submodules

A very nice feature available on git is the possibility of using modules, for example when you clone CakePHP repository you could get DebugKit as a submodule, if you want to clone the main repository + submodules, use following command:

git clone --recursive https://github.com/alex-arriaga/universidad-del-pastel.git

1	git clone --recursive https://github.com/alex-arriaga/universidad-del-pastel.git

Adding a new submodule

git submodule add <GIT_REPO_URL> <SUBMODULE_NAME>
 
// Example
git submodule add https://github.com/twbs/bootstrap.git bootstrap

git submodule add <GIT_REPO_URL> <SUBMODULE_NAME>

// Example

git submodule add https://github.com/twbs/bootstrap.git bootstrap

If someone else added a new submodule, and you want to get submodules, you will need to use the update operation to obtain the module recently added:

git submodule update --init --recursive

1	git submodule update --init --recursive

Changing a submodule for another one

Update .gitmodules with the path to the new repository
Remove the corresponding line from the “.git/config” file
Delete the corresponding directory in the “.git/modules/modules/YOUR_OLD_SUBMODULE” directory (rm -rf)
Delete the checked out submodule directory itself (unsure if this is necessary)
Run:

git submodule init and git submodule update

1	git submodule init and git submodule update

Make sure the checked out submodule is at the correct commit, and commit that, since it’s likely that the hash will be different

Working with remotes

Forcing a push in origin (remote) to a previous version as in our local repository

// Suppose you want to return to a previous version
// in your local repository
git reset --hard YOUR_COMMIT_ID

// Then, probably you will need to force the remote to stay 
// in the same as your local repository
git push origin master --force

// Or
git push origin master -f

// Suppose you want to return to a previous version

// in your local repository

git reset --hard YOUR_COMMIT_ID

// Then, probably you will need to force the remote to stay

// in the same as your local repository

git push origin master --force

// Or

git push origin master -f

Sometimes if the remote server doesn’t have well-configured SSL certificates, you could get an error. If you want to disable SSL verification which I don’t recommend, use next command:

// Disable the SSL CERT verify globally
git config --global http.sslVerify false

// Disable the SSL CERT verify only in current repository
git config http.sslVerify false

// Disable the SSL CERT verify globally

git config --global http.sslVerify false

// Disable the SSL CERT verify only in current repository

git config http.sslVerify false

Changing the URL of a remote:

git remote set-url <REPOSITORY_NAME> <NEW_URL>

// Example
git remote set-url origin git://new.url.here

git remote set-url <REPOSITORY_NAME> <NEW_URL>

// Example

git remote set-url origin git://new.url.here

Deleting remote branches

// List all the branches (local and remote)
git branch -a

// Delete a branch
git push origin --delete MY_BRANCH

// List all the branches (local and remote)

git branch -a

// Delete a branch

git push origin --delete MY_BRANCH

alex-arriaga June 13, 2014

Session 4 – grep command (UNIX and Linux commands, in Spanish)

GNU/Linux, Mac OSX, Operating Systems No Reply

In my life as a front-end and back-end developer, I am searching for very specific strings in thousands of files and directories, so one of my favorite commands in UNIX and Linux is the grep command. This awesome command is able to find complex strings based on patterns.

Watch this video and learn how to use and make your life easier. Enjoy and share the video, and remember be happy with your console!

alex-arriaga June 13, 2014

Session 3 – mkdir command (UNIX and Linux commands, in Spanish)

GNU/Linux, Mac OSX, Operating Systems No Reply

How many times do you create directories (folder) in your computer? I know for sure this is one of the most frequent operations in daily work, right? What about if I tell you there is a great command for UNIX and Linux for fast creation of any directory or directories you want!

Well, watch this video and become in a master of creation of directories. Enjoy and share if you liked it!

alex-arriaga June 13, 2014

Session 2 – chmod command (UNIX and Linux commands, in Spanish)

GNU/Linux, Mac OSX, Operating Systems 1 Reply

A very common operation in UNIX-like and Linux operating systems is to set permissions to files and directories, I have seen many people suffering because of these permissions, so today I am going to explain you how to use the chmod command, with this command you will be able to modify any permissions in the file system.

So, let´s start with the video I hope you find it useful for your daily work. Enjoy it!

alex-arriaga June 13, 2014

Session 1 – ls command (UNIX and Linux commands, in Spanish)

GNU/Linux, Mac OSX, Operating Systems 1 Reply

Console-128

This is the first video about UNIX and Linux commands, in this session we are going to learn how to use the ls command which allows us to get a list directories and files. Enjoy and share this video, and remember be happy with your code!

alex-arriaga May 6, 2014

How to rename files recursively deleting white spaces in file names with shell script

GNU/Linux, Mac OSX, Operating Systems No Reply

Hi!

Today, I would like to share a small script (in shell) to rename files recursively but replacing white spaces in the files’ names. For this task I have only used standard commands in order to be sure this script will work on any GNU/Linux or UNIX-like operating system (mv, sed, find,..). Enjoy and personalize this script as you need!

# Finding all files in a directory and its children
path_to_images="/Users/alex/Downloads/images"

find $path_to_images -type f -name *.jpg -follow |
while read -r file;
do
	file_name="${file##*/}"
	directory=$(dirname "$file")

	# Delete all the whitespaces in file name using sed
	new_file_name=$(echo $file_name | sed 's/ /-/g')
	new_path=$directory'/'$new_file_name
	mv "$file" "$new_path";
	echo "Renamed: $new_path"
done

# Finding all files in a directory and its children

path_to_images="/Users/alex/Downloads/images"

find $path_to_images -type f -name *.jpg -follow |

while read -r file;

file_name="${file##*/}"

directory=$(dirname "$file")

# Delete all the whitespaces in file name using sed

new_file_name=$(echo $file_name | sed 's/ /-/g')

new_path=$directory'/'$new_file_name

mv "$file" "$new_path";

echo "Renamed: $new_path"

done

Most important lines are:

find $path_to_images -type f -name *.jpg -follow

1	find $path_to_images -type f -name *.jpg -follow

Which obtains all the files with .jpg extension starting from $path_to_images, and these other lines:

new_file_name=$(echo $file_name | sed 's/ /-/g')
new_path=$directory'/'$new_file_name

1 2	new_file_name=$(echo $file_name \| sed 's/ /-/g') new_path=$directory'/'$new_file_name

Which replace all white spaces for a dash “-“, in the current $file_name and then by using the mv command the renaming operation is executed.

That’s it!

Be happy with your code!

alex-arriaga November 2, 2013

How to rename files recursively with shell script on GNU/Linux and UNIX-like operating systems

GNU/Linux, Mac OSX, Operating Systems No Reply

Imagine next situation:

You have too many files without extension but you know they are valid HTML files, so you have to add an “.html” extension to all these files.

Now, if you need to rename thousands of files you will need to do it with a script, definitely.

In order to make this happen, you have to choose in which language the program would work better…, if you have a GNU/Linux or a UNIX-like operating system, then you have one of the most powerful tools to manage files and directories: the shell.

When we create a script that runs in the command line, we say: “the script is a shell script“.

Today, I would like to share a short shell script that allows you rename files recursively starting in a base directory:

# Author: Alex Arriaga (@alex_arriaga_m)
# A small shell script for adding an "html" extension to files that don't contain a extension
# For example: "index" will be renamed to "index.html"
# Function: contains(string, substring)
#
# Returns 0 if the specified string contains the specified substring,
# otherwise returns 1.
contains() {
    string="$1"
    substring="$2"
    if test "${string#*$substring}" != "$string"
    then
        return 0    # $substring is in $string
    else
        return 1    # $substring is not in $string
    fi
}

# Finding all files in a directory
root_path_to_content="/home/my-root-directory-for-renaming"

find $root_path_to_content -type f -follow |
while read -r file;
do
	extension=`echo ${file##*.}`
	file_name=`echo ${file%.*}`
	num_chars_ext=`echo ${#extension}`
	num_chars_max_ext=5
	new_extension="html"

	if [[ "$num_chars_ext" -gt "$num_chars_max_ext" ]]; then
		#Verifying if basename contains a "dot" symbol in order to avoid renaming hidden files
		contains `basename $file` "." || echo "Rename: ".`basename $file`
		contains `basename $file` "." || mv $file $file.$new_extension

	#else
		#echo "no"
	fi
done

# Author: Alex Arriaga (@alex_arriaga_m)

# A small shell script for adding an "html" extension to files that don't contain a extension

# For example: "index" will be renamed to "index.html"

# Function: contains(string, substring)

# Returns 0 if the specified string contains the specified substring,

# otherwise returns 1.

contains() {

string="$1"

substring="$2"

if test "${string#*$substring}" != "$string"

then

return 0 # $substring is in $string

else

return 1 # $substring is not in $string

}

# Finding all files in a directory

root_path_to_content="/home/my-root-directory-for-renaming"

find $root_path_to_content -type f -follow |

while read -r file;

extension=`echo ${file##*.}`

file_name=`echo ${file%.*}`

num_chars_ext=`echo ${#extension}`

num_chars_max_ext=5

new_extension="html"

if [[ "$num_chars_ext" -gt "$num_chars_max_ext" ]]; then

#Verifying if basename contains a "dot" symbol in order to avoid renaming hidden files

contains `basename $file` "." || echo "Rename: ".`basename $file`

contains `basename $file` "." || mv $file $file.$new_extension

#else

#echo "no"

done

That’s it!

Be happy with your code!

alex-arriaga September 4, 2013

How to authenticate in a Linux server without password (configuring SSH keys in MAC OS X or any UNIX-like Operating System)

GNU/Linux, Operating Systems, Uncategorized No Reply

When you need to connect to several servers because you need to share, update or syncronize a set of files, a common situation is authentication process with the server, if you do this several times in a day, it could be a little hard to type or input your password every time that you are connecting, so, for this reason today I would like to explain how to configure your machine in order to have an authentication based on RSA keys, on this way, no password will be required anymore (an UNIX-like operating system is required, it doesn’t apply for windows, sorry).

Preparing client

First, be sure that you have generated your private and public keys in your CLIENT MACHINE, to do this you can use next command:

ssh-keygen -t  rsa

1	ssh-keygen -t rsa

This command will generate a new directory in your home folder called .ssh as you can see it is a hidden directory, inside of it you can find at least next files:

Use next command to go to your home folder:

cd ~

cd ~

If you want to list all files -included hidden files- just type (see figure 1):

ls -la

ls -la

Figure 1. An example of ls -la command.

If you can’t see all these files, don’t worry, at least you should see next two files:

id_rsa. This file saves your private key (you must NOT share this key is only for you).
id_rsa.pub. This file contains your public key (you can share this key with all your “server-friends”).

Configuring server

Now, it is time to prepare your server to allow access using public keys authentication.

1) Go to next directory: /etc/ssh/

cd /etc/ssh/

1	cd /etc/ssh/

2) Back up the file called sshd_config (to save the original file, just in case you have a configuration error and you need to return to previous configuration). This file contains configuration used by SSH service.

cp sshd_config sshd_config_backup

1	cp sshd_config sshd_config_backup

3) Open sshd_config file:

nano sshd_config

1	nano sshd_config

4) Inside of it try to find next lines, in case they don’t exist you can add at the end the file:

PubkeyAuthentication yes
AuthorizedKeysFile      %h/.ssh/authorized_keys

1 2	PubkeyAuthentication yes AuthorizedKeysFile %h/.ssh/authorized_keys

First line allows the use of public keys to authentication.
Second one specifies where the public keys will be stored.

5) Save and close the file (press Ctrl + O to save and Ctrl + X to close).

6) Now, we will add our public key to authorized_keys file, to do this, open this file (it usually is in ~/.ssh/authorized_keys, in case it doesn’t exist you can create it).

nano ~/.ssh/authorized_keys

1	nano ~/.ssh/authorized_keys

7) Next, this is too important: you MUST copy YOUR public key, this key is in YOUR COMPUTER in the file id_rsa.pub (generated with ssh-keygen at the beginning of this post). You will need to open your id_rsa.pub file, copy its content and paste at the end of the authorized_keys file in the SERVER (if you want you can backup authorized_keys before adding your public key).

8) To see this changes you must restart SSH service:

CentOS / RHEL / Fedora / Redhat Linux Restart SSH

/etc/init.d/sshd restart

OR

service sshd restart

/etc/init.d/sshd restart

service sshd restart

Debian / Ubuntu Linux Restart SSH

/etc/init.d/ssh restart

OR

service ssh restart

/etc/init.d/ssh restart

service ssh restart

FreeBSD Restart SSH

/etc/rc.d/sshd restart

1	/etc/rc.d/sshd restart

9) Close your current SSH connection.

exit

exit

10) Finally, to test all your configuration, just try to enter to the server and you should enter without password!

That’s it!

Be happy with your servers.

—

Alex Arriaga

alex-arriaga August 20, 2013

How to check MD5 Hash in Mac OS X or any UNIX-like Operating System

GNU/Linux, Mac OSX, Operating Systems No Reply

Today, after downloading a new version of a Linux distribution, I needed to check MD5 Hash in order to verify if the ISO file had not any error. This is a common task for IT people, for this reason, I would like to share with you the easiest way to get the MD5 Hash in Mac OS X:

1) Open a terminal

2) Use the command: md5 name_of_file for example. My file was: LT-DVD-x86_64-GM-DVD1.iso

md5 LT-DVD-x86_64-GM-DVD1.iso

1	md5 LT-DVD-x86_64-GM-DVD1.iso

After running previous command you will obtain an output like this:

MD5 (LT-DVD-x86_64-GM-DVD1.iso) = e79339d7e29405deb09b7d2372dd80f2

1	MD5 (LT-DVD-x86_64-GM-DVD1.iso) = e79339d7e29405deb09b7d2372dd80f2

3) Compare MD5 obtained with the MD5 Hash published by distributor (it is common that people who upload the file, also upload the MD5 codes). For example, in my case I checked that my Linux was damaged because these codes didn’t coincide 🙁 so it was necessary to download again.

4) An alternative command to get the same result is: openssl md5 name_of_file. As you can see, it doesn’t matter which command you choose, both of them will return the same hash.

openssl md5 LT-DVD-x86_64-GM-DVD1.iso

1	openssl md5 LT-DVD-x86_64-GM-DVD1.iso

That’s it!

Be happy with your code!

—

Alex Arriaga

alex-arriaga July 23, 2013

How to set directory and files permissions for a Joomla site in a production environment

GNU/Linux, Joomla, Operating Systems, Web Development 2 Replies

When you have a project created on Joomla CMS, you will need to protect your directories and files in order to avoid a possible attack or loosing information. During my time as a web developer and as a server admin in Government I learnt about what’s is a good configuration for setting permissions, for this reason I would like to share a list of commands that you can use in your own server. This set of commands apply to a GNU/Linux or UNIX-like operating systems, obviously I don’t recommend use IIS from Microsoft (I am sorry Microsoft, but PHP + IIS is NOT a good option).

In a nutshell, you can use these commands:

find /YOUR_SERVER_PATH/YOUR_ROOT_JOOMLA_DIRECTORY -type f -print0 | xargs -0 chmod 644
find /YOUR_SERVER_PATH/YOUR_ROOT_JOOMLA_DIRECTORY -type d -print0 | xargs -0 chmod 755
chmod -R g+w /YOUR_SERVER_PATH/YOUR_ROOT_JOOMLA_DIRECTORY/images
chmod -R g+w /YOUR_SERVER_PATH/YOUR_ROOT_JOOMLA_DIRECTORY/cache
chmod -R g+w /YOUR_SERVER_PATH/YOUR_ROOT_JOOMLA_DIRECTORY/tmp

find /YOUR_SERVER_PATH/YOUR_ROOT_JOOMLA_DIRECTORY -type f -print0 | xargs -0 chmod 644

find /YOUR_SERVER_PATH/YOUR_ROOT_JOOMLA_DIRECTORY -type d -print0 | xargs -0 chmod 755

chmod -R g+w /YOUR_SERVER_PATH/YOUR_ROOT_JOOMLA_DIRECTORY/images

chmod -R g+w /YOUR_SERVER_PATH/YOUR_ROOT_JOOMLA_DIRECTORY/cache

chmod -R g+w /YOUR_SERVER_PATH/YOUR_ROOT_JOOMLA_DIRECTORY/tmp

For example, if my SERVER_PATH is something like this: /var/www/ and my ROOT_JOOMLA_DIRECTORY is digital-newspaper, then we can use this commands:

# This line sets all files inside of digital-newspaper to "644" permissions
find /var/www/digital-newspaper -type f -print0 | xargs -0 chmod 644

# Setting all directories to "755"
find /var/www/digital-newspaper -type d -print0 | xargs -0 chmod 755

# Special group permissions are necessary in images, cache and tmp directories
chmod -R g+w /var/www/digital-newspaper/images
chmod -R g+w /var/www/digital-newspaper/cache
chmod -R g+w /var/www/digital-newspaper/tmp

# This line sets all files inside of digital-newspaper to "644" permissions

find /var/www/digital-newspaper -type f -print0 | xargs -0 chmod 644

# Setting all directories to "755"

find /var/www/digital-newspaper -type d -print0 | xargs -0 chmod 755

# Special group permissions are necessary in images, cache and tmp directories

chmod -R g+w /var/www/digital-newspaper/images

chmod -R g+w /var/www/digital-newspaper/cache

chmod -R g+w /var/www/digital-newspaper/tmp

So, that’s it!

Be happy with your servers!

—

Alex Arriaga

What would you like to know about?

Alex Arriaga

Category Archives:
GNU/Linux

Some useful Git commands

Configuring your Git

Managing Git repositories

Restoring files

Working with branches

Working with submodules

Working with remotes

Session 4 – grep command (UNIX and Linux commands, in Spanish)

Session 3 – mkdir command (UNIX and Linux commands, in Spanish)

Session 2 – chmod command (UNIX and Linux commands, in Spanish)

Session 1 – ls command (UNIX and Linux commands, in Spanish)

How to rename files recursively deleting white spaces in file names with shell script

How to rename files recursively with shell script on GNU/Linux and UNIX-like operating systems

How to authenticate in a Linux server without password (configuring SSH keys in MAC OS X or any UNIX-like Operating System)

Preparing client

Configuring server

How to check MD5 Hash in Mac OS X or any UNIX-like Operating System

How to set directory and files permissions for a Joomla site in a production environment

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What would you like to know about?

Category Archives:GNU/Linux

Configuring your Git

Managing Git repositories

Restoring files

Working with branches

Working with submodules

Working with remotes

Preparing client

Configuring server

Join me, have fun and learn!

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