Join Kevin Skoglund for an in-depth discussion in this video Configuring history with variables, part of Unix for Mac OS X Users.
Environment variables can be very helpful in allowing us to customize how…the Unix history works.…There are five different variables that we can configure.…Before we start looking at them, let's first start by just using history -c to…clear out our existing history so that everything we work with we'll be able to…easily identify what's new and what's been added to the history, and then let's…do nano .bashrc and right below where we set our path I am just going to paste…in the lines for the history and then we can talk to them and that way you don't…have to sit and watch me type.…
So notice that on each of them I'm exporting it and here is the variable name.…HISTSIZE, HIST being short for history, HISTSIZE= and then a number.…This is the number of commands that history will remember.…By default it will remember 500.…If you want more or less, well this is how you change it. You set the variable here.…Once we get to that maximum number then the oldest command will drop off the top…and it will still just add the newest command at the bottom.…
- 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
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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