CISC 5500 Data Analytics Tools and Scripting find and grep Computer - - PowerPoint PPT Presentation

CISC 5500 Data Analytics Tools and Scripting

find and grep

Computer and Information Science

Fordham University

Table of contents

• 1. find
• 2. grep

1

review

myfunc () { # do something here } if [ some condition ] then # do something here fi while [ some condition ] do # do something here done for item in item1 item2 item3 do # do something here done

2

find

find

Search for files in a directory hierarchy. A simple example: find all the files called something dot jpg under the current directory. find . -name "*.jpg"

3

grep

grep

Print lines matching a pattern. A simple example: find all the lines that contains ’test’ in all the files in the current directory grep test *

4

xargs

Build and execute command lines from standard input. A simple example: compare cat and echo, but the ’argument’ is unknown when the command is entered xagrs echo xargs cat Real application: downstream of the pipe

5

scp

Copy between different computers. A simple example: get a file from my account on the storm server scp ji@storm.cis.fordham.edu:~/test2.txt .

6

Summary

• find
• grep

2020.9.17 7

Questions?

7

regular expression

Regular expression is a formal language to specify patterns.

• line beginning and ending ^ $
• dot (matching all) and character set []
• quantification (repetition operators)
• ?
• *
• +