GREP(1) BSD General Commands Manual GREP(1)
NAME
grep, egrep, fgrep, zgrep, zegrep, zfgrep -- file pattern searcher
SYNOPSIS
grep [-abcdDEFGHhIiJLlmnOopqRSsUVvwxZ] [-A num] [-B num] [-C[num]] [-e pattern] [-f file] [--binary-files=value] [--color[=when]] [--colour[=when]]
[--context[=num]] [--label] [--line-buffered] [--null] [pattern] [file ...]
DESCRIPTION
The grep utility searches any given input files, selecting lines that match one or more patterns. By default, a pattern matches an input line if the regular
expression (RE) in the pattern matches the input line without its trailing newline. An empty expression matches every line. Each input line that matches at
least one of the patterns is written to the standard output.
grep is used for simple patterns and basic regular expressions (BREs); egrep can handle extended regular expressions (EREs). See re_format(7) for more informa-
tion on regular expressions. fgrep is quicker than both grep and egrep, but can only handle fixed patterns (i.e. it does not interpret regular expressions).
Patterns may consist of one or more lines, allowing any of the pattern lines to match a portion of the input.
zgrep, zegrep, and zfgrep act like grep, egrep, and fgrep, respectively, but accept input files compressed with the compress(1) or gzip(1) compression utili-
ties.
The following options are available:
-A num, --after-context=num
Print num lines of trailing context after each match. See also the -B and -C options.
-a, --text
Treat all files as ASCII text. Normally grep will simply print ``Binary file ... matches'' if files contain binary characters. Use of this option
forces grep to output lines matching the specified pattern.
-B num, --before-context=num
Print num lines of leading context before each match. See also the -A and -C options.
-b, --byte-offset
The offset in bytes of a matched pattern is displayed in front of the respective matched line.
-C[num, --context=num]
Print num lines of leading and trailing context surrounding each match. The default is 2 and is equivalent to -A 2 -B 2. Note: no whitespace may be
given between the option and its argument.The argparse module has us covered!
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# For demo purposes only
import sys
sys.argv = ['greetme.py', '--name', 'John', '--greeting', 'Hola,']
In [ ]:
import argparse
# Create an instance
parser = argparse.ArgumentParser(description='A simple program that prints a greeting to the name specified')
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# Add a name argument
parser.add_argument('--name', type=str, required=True, help='Name of the person being greeted')
parser.add_argument('--greeting', type=str, default='Hello, ', help='Greeting to be used')
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# Parse the arguments
args = parser.parse_args()
In [ ]:
# Print the greeting
print(f'{args.greeting} {args.name}')