LAPTOP i7

diff rcs file

rcsdiff -r1.1 -r1.2 -u file

here we are diffing rev 1.2 agains 1.1


If you want to colour the output you can use the idiff script

rcsdiff -r1.1 -r1.2 -u file | ./idiff

Display File Content with Colors and Line Number Alternative to cat Ubuntu

Sometimes you may want to quickly display the contents of a file directly on the command line with the `cat` command. And sometimes the contents of that file is the source code of a program.

If you want to display the source code markup with colors and line numbers, then this trick is what you are looking for.

What you need to do first is install Pygments, a python syntax highlighter.

sudo apt-get install python-pygments python3-pygments

After installing pygments, you can now view source code with colored markups. just run the ff:

pygmentize testfile.rb

Now for the line numbers, you will have to pipe the `nl` command

pygmentize testfile.rb | nl --body-numbering=a

The option

--body-numbering

means it will accept a style for line numbering and it is any of the ff:

a - number all lines
t - number only nonempty lines
n - number no lines

I used a so that everything will be numbered including empty lines.

We can actually add nl options in bash alias so that we do not have to type it everytime.

alias nl=nl --body-number=a

While at it, lets also shorten the pygmentize command.

alias ccat=pygmentize

Now the source code syntax will be highlighted everytime we ran this command:

ccat testfile.rb | nl

Django Reminder Delete File when deleting object

For Django FileField objects and object of its subclasses, when using the objects delete() method, it will only delete the object record from the database, the file will remain in the appointed location in your servers filesystem.

After a few research, it is a deliberate design in Django to prevent unwanted mess in database when rolling back an record (not sure how this is doable though, leave comments if you know how :D).

So, we have to explicitly delete the file from the filesystem ourselves using

FileFieldObject.file_field.storage.delete(filepath)

A simple implementation to delete the file when delete the file object from db would be like this:

f = FileFieldObject #replace with your models .objects.get() here

storage = f.file_field.storage

#field_field is the property in your model which is an object of class model.FileField

path = f.field_field.path

storage.delete(path) #delete file from disk
f.delete() #delete record from db

Django Remind Image File upload handling and retrieving

The handling of image/file in Django is a bit complicated than PHP, since PHP basically uses HTML syntax to display a file.

Django ImageField rename file on upload

By default Django keeps the original name of the uploaded file but more than likely you will want to rename it to something else (like the objects id). Luckily, with ImageField or FileField of Django forms, you can assign a callable function to the upload_to parameter to do the renaming. For example:


from django.db import models
from django.utils import timezone
import os
from uuid import uuid4

def path_and_rename(instance, filename):
    upload_to = photos
    ext = filename.split(.)[-1]
    # get filename
    if instance.pk:
        filename = {}.{}.format(instance.pk, ext)
    else:
        # set filename as random string
        filename = {}.{}.format(uuid4().hex, ext)
    # return the whole path to the file
    return os.path.join(upload_to, filename)


class CardInfo(models.Model):
    id_number = models.CharField(max_length=6, primary_key=True)
    name = models.CharField(max_length=255)
    photo = models.ImageField(upload_to=path_and_rename, max_length=255, null=True, blank=True)

In this example, every image that is uploaded will be rename to the CardInfo objects primary key which is id_number.


Reference: http://stackoverflow.com/questions/15140942/django-imagefield-change-file-name-on-upload