Join Kevin Skoglund for an in-depth discussion in this video grep: Searching for matching expressions, part of Unix for Mac OS X Users.
In this chapter we're going to take a look at some of the most useful and…powerful Unix commands.…Up until now we've really been covering the fundamentals and getting familiar…with Unix, but now we are at the point where we can start doing some serious…work, and the most powerful tool in the Unix toolbox by far is grep.…Grep is a powerful way for us to search for text which matches patterns that we…specify, and we aren't just talking about searching for simple text strings.…We can define complex matching patterns by using regular expressions, and regular…expression are actually part of how grep gets its name.…
Grep stands for Global Regular Expression Print.…If you think back to the movie where we talked about Unix text editors, I told…you that the earliest Unix text editor was called ed or Ed, and if you were…working inside the ed text editor and you wanted to search for something, the…way you did it was by typing a g, then a forward slash and then a regular…expression that described what you were going to search for, another forward…
- Moving around the file system
- Creating and reading files
- Copying, moving, renaming, and deleting files and directories
- Creating hard links and symbolic links
- Understanding user identity, file ownership, and sudo
- Setting file permissions with alpha and octal notation
- Changing the PATH variable
- Using the command history
- Directing input and output
- Configuring the Unix working environment
- Searching and replacing using grep and regular expressions
- Manipulating text with tr, sed, and cut
- Integrating with the Finder, Spotlight, and AppleScript
Skill Level Beginner
Q: The exercise files for the following movies appear to be broken:
Is there something wrong with them?
These exercises include one or more "dot files", whose file names start with a period. These files are normally hidden from view by the Finder. So that they would show up in the Finder, the period has been removed from the file names. Additionally, "_example" has been added at the end of the file name to make it clear that the file will not work as-is.
To make the dot files usable, either:
1) Open the file in a text editor to view its contents. Note that it may not be possible to double-click the file to open it because there is no file extension (such as .txt).
2) Resave the file under a new name (usually by choosing File > Save As), adding a "." to the beginning of the file name and removing "_example" from the end.
1) Copy and rename the file from the Unix command line using the techniques discussed in this course. Rename the file by adding a "." to the start and removing "_example" from the end. Include the "-i" option to prevent overwriting an existing file unexpectedly.
Example: cp -i ~/Desktop/Exercise\ Files/Chapter_07/07_02_files/bashrc_example ~/.bashrc
The instructor uses the UNIX program 'units' to convert 72° Fahrenheit to degrees Celsius. The returned value of 40 is incorrect. The correct result should be 22°C. What's the reason for this discrepancy?
The problem is that units does the 5/9 calculation but does not have the ability to subtract 32. So you'll need to subtract (or add) the 32 degrees yourself.
1. Introduction to Unix
2. Filesystem Basics
3. Working with Files and Directories
4. Ownership and Permissions
5. Commands and Programs
6. Directing Input and Output
7. Configuring Your Working Environment
8. Unix Power Tools
9. Useful Mac-Only Commands and Techniques
- Mark as unwatched
- Mark all as unwatched
Are you sure you want to mark all the videos in this course as unwatched?
This will not affect your course history, your reports, or your certificates of completion for this course.Cancel
Take notes with your new membership!
Type in the entry box, then click Enter to save your note.
1:30Press on any video thumbnail to jump immediately to the timecode shown.
Notes are saved with you account but can also be exported as plain text, MS Word, PDF, Google Doc, or Evernote.