sed linux command:

sed stands for Stream Editor. As its name advertise it works on stream of text (input file, input pipleline).
General command executation:

sed REGEX INPUTFILE

For instance if you want to replace hi with bye in hibye.txt file:

sed 's/hi/bye/' hibye.txt

It will print the result into standard output (console). If you want to put the output in a file:

sed 's/hi/bye/' hibye.txt > output.txt

Instead of INPUTFILE we can put - which then reads from standard input:

cat hibye.txt | sed 's/hi/bye/' -

Now if you want to put the output in a file:

cat hibye.txt | sed 's/hi/bye/' - > output.txt

As until now you have seen, sed command writes output to standard output, if you want to write the result to the file itself, use -i as below:

sed -i 's/hi/bye' hibye.txt

So in the above command the result will be written to hibye.txt itself.

#linux #sed #regex

#python #django #django_part11 #views #render

In this tutorial we would go over rendering templates by using shortcuts and using dynamic urls in views. We also complete the detail function to load question details from database.

#django_part11

جلسه ۵۰ گروه کاربران پایتون تهران، فردا پنجشنبه ۹ آذر ۱۳۹۶ از ساعت ۱۴:۳۰ تا ۱۶:۰۰ در «شتاب‌دهندهٔ آواتک» به نشانی «جاده مخصوص کرج، جنب متروی بیمه، خط کندرو، بین کوچه بیمه 2 و بیمه 3، پلاک 31، (محل سابق کارخانه الکترودسازی آما) کارخانه نوآوری، آواتک» برگزار خواهد شد.
شرکت در این رویداد برای کلیه علاقمندان، آزاد و رایگان است.
#python #tehpug #meetup

About the author
Susan Fowler is a site reliability engineer at Uber Technologies, where she splits her time between running a production-readiness initiative across all Uber microservices and embedding within business-critical teams to bring their services to a production-ready state. She worked on application platforms and infrastructure at several small startups before joining Uber.

Export all collection documents in MongoDB to a JSON file:

mongoexport --db YOUR_DATABASE --collection YOUR_COLLECTION_NAME --out YOUR_OUTPUT_FILE_NAME.json

NOTE: do not use this command for full database backup! Use mongodump instead

#mongodb #export #mongoexport #mongodump #collection #database

Install htop on CentOS from source:

htop is a real-time process viewer for Linux. First, install prerequisites and download the source:

yum groupinstall "Development Tools"
 yum install ncurses-devel
 wget http://hisham.hm/htop/releases/2.0.2/htop-2.0.2.tar.gz
 tar xvfvz htop-2.0.2.tar.gz
 cd htop-2.0.2/

Prepare for compilation:

./configure

By default, htop will be installed under /usr/local/bin. If you want to change installation location to something else (e.g., /usr/ bin`), run configure script with `--prefix option instead. For example:

./configure --prefix=/usr

build and install htop as follows:

make
 make install

Voila! You're done. just run it using:

htop

#linux #centos #htop #compile #source #install

https://auth0.com/blog/secure-your-react-and-redux-app-with-jwt-authentication/

#react #redux #js #jwt #authentication #auth0

For REST APIs it usually happens to encode client-id and client-secret to send to an endpoint to get access token.
It has been said in API documentation that send data like below:

Basic BASE64_ENCODEDED_VALUE_OF(CLIENT_ID:CLIENT_SECRET)

There is an online tool for exactly that specific purpose (encode, decode base64).

Go to link below:
- https://www.base64encode.org/

#base64 #base64encode #client_id #client_secret #api #rest #webservice

You are on a server and all of a sudden you need your public IP address. You can do it using cURL and terminal:

$ curl ifconfig.co
 142.17.150.17

The website will just spit out the IP address with no bullshit around it! It is more specifically used by sysadmins.

#linux #sysadmin #curl #ifconfig #ifconfigco

In order to load json config file in Cement python framework, you simply need to include the json extension, and then set the CementApp.Meta.config_handler to json:

from cement.core.foundation import CementApp

 class MyApp(CementApp):
     class Meta:
         label = 'myapp'
         extensions = ['json']
         config_handler = 'json'
         config_extension = '.json'

This will keep the default config_files list intact, but use .json instead of .conf for the files it looks for.

#python #cement #json #config

In case you want to store special characters inside of MySQL table field, you need to change the table encoding like below:

ALTER TABLE YOUR_TABLE CONVERT TO CHARACTER SET utf8 COLLATE utf8_unicode_ci;

#database #mysql #charset #character_set #collate #utf8 #utf8_unicode_ci #alter

Simplify chained comparison

It sometimes happen you write code in python like below:

if your_date >= start_date and your_date <= end_date:
     pass

You can simplify the code above as below:

if start_date <= issue_date <= end_date:
     pass

This kind of comparison is called chained comparison in a simplified manner.

#python #if #chained_comparison

So true!
#comic #fun #programmer_jokes

How to get method name in python?

The inspect module provides several useful functions to help get information about live objects such as modules, classes, methods, functions, tracebacks, frame objects, and code objects. For example, it can help you examine the contents of a class, retrieve the source code of a method, extract and format the argument list for a function, or get all the information you need to display a detailed traceback.

You can use inspect module to do exactly this job:

curframe = inspect.currentframe()
 calframe = inspect.getouterframes(curframe, 2)
 caller_method = calframe[0][3]

The part that you are interested in, is calframe[0][3]. It returns function name of the current method. If this method is called from a parent method (caller method), you have to get that method name using calframe[1][3].

A sample code for the inspect module:

import inspect


 class PDFtoJPG:
     def _internal_conversion(self):
         self.convert_to_jpg()

     def convert_to_jpg(self):
         curframe = inspect.currentframe()
         calframe = inspect.getouterframes(curframe, 2)
         print calframe[0][3]
         print calframe[1][3]
         print calframe[2][3]

     def convert(self):
         self._internal_conversion()


 snd = PDFtoJPG()
 snd.convert()

#python #inspect #calframe #method_name

You can also use inspect.stack()[2][3] instead of getting current frame and then getting its outer frames:
inspect.stack returns a list of frame records for the caller’s stack. The first entry in the returned list represents the caller; the last entry represents the outermost call on the stack.

#python #inspect #stack

How to work with stash in git?

Often, when you’ve been working on part of your project, things are in a messy state and you want to switch branches for a bit to work on something else. The problem is, you don’t want to do a commit of half-done work just so you can get back to this point later. The answer to this issue is the git stash command.

Stashing takes the dirty state of your working directory — that is, your modified tracked files and staged changes — and saves it on a stack of unfinished changes that you can reapply at any time.

Now you want to switch branches, but you don’t want to commit what you’ve been working on yet, to stash your modified files in your project use git stash:

$ git stash
 Saved working directory and index state \
   "WIP on master: 049d078 added the index file"
 HEAD is now at 049d078 added the index file
 (To restore them type "git stash apply")

Now your working directory should be clean:

$ git status
 # On branch master
 nothing to commit, working directory clean

To list all your stashes use git stash list:

$ git stash list
 stash@{0}: WIP on master: 049d078 added the index file
 stash@{1}: WIP on master: c264051 Revert "added file_size"
 stash@{2}: WIP on master: 21d80a5 added number to log

Now if you want to apply the most recent stashed files:

$ git stash apply
 # On branch master
 # Changes not staged for commit:
 #   (use "git add <file>..." to update what will be committed)
 #
 #      modified:   index.html
 #      modified:   lib/simplegit.rb

In order to remove a stash, use git stash drop YOUR_STASH:

$ git stash list
  stash@{0}: WIP on master: 049d078 added the index file
  stash@{1}: WIP on master: c264051 Revert "added file_size"
  stash@{2}: WIP on master: 21d80a5 added number to log
 $ git stash drop stash@{0}
  Dropped stash@{0} (364e91f3f268f0900bc3ee613f9f733e82aaed43)

These are some general, most useful commands to work with stash. Enjoy the article :)

#git #stash #stash_apply #stash_list #stash_drop #stash_save