IT/Software/Command Line
Welcome to the dark world where most IT people live
- This is a gui free world
- If you don't know what a gui is please quietly close the page and go buy a slurpee
- If you don't know what a slurpee is we feel sorry for you.
Basic Commands
Find
This will help you find files and/or folders. Its power is amazing. It is often used in conjunction with commands. First find something and then do something.
find directory -user username
Directory is relative unless you specify absolute
Changing Ownership
There are many ways to do this. Half of them may be more clever.
sudo chown walt:walt /path/to/filename
This will make the file filename belong to the user walt and the group walt. Usually we change the group and user at the same time.
OR
sudo chown user:group /path/to/directory/
This changes only the directory to user and group specified
Adding the -R flag after the chown will recurse into directories and files.
sudo chown -R . . .
- We are not sure why the capital r is needed in some cases. But it is here.
Changing Permissions
This is very similar except we use chmod instead of chown
sudo chmod 644 /path/to/file or path/to/directory/
Adding the -R flag does the same as above.
Change all files recursively to 644
find /var/www/html/moodlecnx/ -type f -exec chmod 644 {} \;
Change all directories recursively to 755
find /var/www/html/moodlecnx/ -type d -exec chmod 755 {} \;
Mount and Unmount
iso files
sudo mkdir /mnt/iso
sudo mount -o loop Win10_2004_English_x64.iso /mnt/iso
Symlinks
This allows you to click on a folder or directory and actually end up somewhere else.
For example if a user can't figure out how to get to the Documents folder from Dolphin.ln -s /real/file/or/folder/path /path/to/link
The link can't already exist.
the path can be a file or directory.
Delete all files in folder tree
This will find all files under the parent directory(absolute) and recursively delete them.
It will not delete hidden files.
find ~/msgcnxFiles/Teacher/Science/Biology/For\ Upload/ -type f -delete
Printing
lp is the classic
lp filename will print the file to the default printer with the default settings
lp -n 3 /path/*.pdf
Much time has been invested in learning this.
Make sure you install the printer correctly or you will get strange errors.
Stay away from "driverless" if you can.
List the default destination
lpstat -d
List the available printers
lpstat -d -p
Print Portrait two sided.
lp -o two-sided-long-edge
3 copies of any pdf file in that path.
-P page-list Specifies pages to print in the document. The list can contain a list of numbers and ranges (#-#) separated by commas, e.g.,
"1,3-5,16". The page numbers refer to the output pages and not the document's original pages
Rename
- This function has many many option. We can only begin here.
- Below is an example where we prepend a 0 onto file names so that they order correctly on all OSes
- This works in the current working directory
rename -e 's/\d+/sprintf("%02d",$&)/e' -- *.jpg