GREP basics¶

grep allows you to search within files.

see what lines in alice in wonderland contain the word watch¶

In [ ]:

%%bash

# see what lines in alice in wonderland contain the word watch
grep watch alice.txt

%%bash # see what lines in alice in wonderland contain the word watch grep watch alice.txt

watch out of its waistcoat-pocket_, and looked at it, and then hurried
watch to take out of it, and burning with curiosity, she ran across the
is it?” he said, turning to Alice: he had taken his watch out of his
The March Hare took the watch and looked at it gloomily: then he dipped
funny watch!” she remarked. “It tells the day of the month, and doesn’t
“Why should it?” muttered the Hatter. “Does _your_ watch tell you what
went nearer to watch them, and just as she came up to them she heard
things—” when his eye chanced to fall upon Alice, as she stood watching
watching it a minute or two, she made it out to be a grin, and she said
The Gryphon sat up and rubbed its eyes: then it watched the Queen till
“Thank you, it’s a very interesting dance to watch,” said Alice,
Alice watched the White Rabbit as he fumbled over the list, feeling
hand, watching the setting sun, and thinking of little Alice and all

search for lines that contain the word chapter¶

In [ ]:

%%bash

# search for lines that contain the word chapter
grep chapter alice.txt
# this returns nothing as there is no line that contains chapter all lowercase.

%%bash # search for lines that contain the word chapter grep chapter alice.txt # this returns nothing as there is no line that contains chapter all lowercase.

---------------------------------------------------------------------------
CalledProcessError                        Traceback (most recent call last)
<ipython-input-5-dfb6264d31bc> in <module>
----> 1 get_ipython().run_cell_magic('bash', '', '\ngrep chapter alice.txt\n')

/shared-libs/python3.7/py-core/lib/python3.7/site-packages/IPython/core/interactiveshell.py in run_cell_magic(self, magic_name, line, cell)
   2397             with self.builtin_trap:
   2398                 args = (magic_arg_s, cell)
-> 2399                 result = fn(*args, **kwargs)
   2400             return result
   2401 

/shared-libs/python3.7/py-core/lib/python3.7/site-packages/IPython/core/magics/script.py in named_script_magic(line, cell)
    140             else:
    141                 line = script
--> 142             return self.shebang(line, cell)
    143 
    144         # write a basic docstring:

/shared-libs/python3.7/py-core/lib/python3.7/site-packages/decorator.py in fun(*args, **kw)
    229             if not kwsyntax:
    230                 args, kw = fix(args, kw, sig)
--> 231             return caller(func, *(extras + args), **kw)
    232     fun.__name__ = func.__name__
    233     fun.__doc__ = func.__doc__

/shared-libs/python3.7/py-core/lib/python3.7/site-packages/IPython/core/magic.py in <lambda>(f, *a, **k)
    185     # but it's overkill for just that one bit of state.
    186     def magic_deco(arg):
--> 187         call = lambda f, *a, **k: f(*a, **k)
    188 
    189         if callable(arg):

/shared-libs/python3.7/py-core/lib/python3.7/site-packages/IPython/core/magics/script.py in shebang(self, line, cell)
    243             sys.stderr.flush()
    244         if args.raise_error and p.returncode!=0:
--> 245             raise CalledProcessError(p.returncode, cell, output=out, stderr=err)
    246 
    247     def _run_script(self, p, cell, to_close):

CalledProcessError: Command 'b'\ngrep chapter alice.txt\n'' returned non-zero exit status 1.

search for lines that contain the word chapter ignoring the case¶

In [ ]:

%%bash

# search for lines that contain the word chapter ignoring the case

grep -i chapter alice.txt

%%bash # search for lines that contain the word chapter ignoring the case grep -i chapter alice.txt

 CHAPTER I.     Down the Rabbit-Hole
 CHAPTER II.    The Pool of Tears
 CHAPTER III.   A Caucus-Race and a Long Tale
 CHAPTER IV.    The Rabbit Sends in a Little Bill
 CHAPTER V.     Advice from a Caterpillar
 CHAPTER VI.    Pig and Pepper
 CHAPTER VII.   A Mad Tea-Party
 CHAPTER VIII.  The Queen’s Croquet-Ground
 CHAPTER IX.    The Mock Turtle’s Story
 CHAPTER X.     The Lobster Quadrille
 CHAPTER XI.    Who Stole the Tarts?
 CHAPTER XII.   Alice’s Evidence
CHAPTER I.
CHAPTER II.
CHAPTER III.
CHAPTER IV.
CHAPTER V.
CHAPTER VI.
CHAPTER VII.
CHAPTER VIII.
CHAPTER IX.
CHAPTER X.
CHAPTER XI.
CHAPTER XII.

search for lines that begin with the word chapter ignoring the case¶

In [ ]:

%%bash

# search for lines that begin with the word chapter ignoring the case

grep -i ^chapter alice.txt

%%bash # search for lines that begin with the word chapter ignoring the case grep -i ^chapter alice.txt

CHAPTER I.
CHAPTER II.
CHAPTER III.
CHAPTER IV.
CHAPTER V.
CHAPTER VI.
CHAPTER VII.
CHAPTER VIII.
CHAPTER IX.
CHAPTER X.
CHAPTER XI.
CHAPTER XII.

Created in Deepnote