Join Kevin Skoglund for an in-depth discussion in this video Reading files, part of Unix for Mac OS X Users.
Now we will learn how to read the contents of a file.…Now you may be thinking, why not to use Nano to open and read the contents of a file?…Well, you certainly can. In fact I do it all the time.…But what we are interested in here are tools which are designed just for reading files.…This difference will become important later because we'll learn that to read a…file really just means to output the text to your screen and we'll learn to…direct that output that places besides our screen and even to other commands.…A tool like nano which depends on user interaction would do too much for us…and it would get in the way.…
Now, we have a couple of options for reading files. The first is cat.…cat is the simplest and the one that you would use most often.…It has kind of a funny name, because cat is short for concatenate.…You see, cat doesn't just read a file.…It will concatenate or join several files together.…You can think of it as read and output the first file, then immediately read and…output the second file, and then the next file and so on.…
- 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
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