linux_flashcards
who
Displays a list of users currently logged into the system, showing their usernames, terminals, login times, and remote hosts if applicable.
exit
Closes the current terminal session and logs you out of the shell. If inside an SSH session, it disconnects you from the remote system.
pwd
Prints the absolute path of the current working directory, which is where you are currently located in the filesystem.
ls
Lists all files and directories in the current working directory. Use ‘ls -l’ for detailed information and ‘ls -a’ to show hidden files.
cp
Copies a file or directory from one location to another. Syntax: ‘cp source_file destination’. Use ‘-r’ to copy directories recursively.
cat
Concatenates and displays the contents of a file directly in the terminal. Useful for quickly viewing file contents.
less
Opens a file for viewing in a scrollable format. Use arrow keys to navigate and press ‘q’ to exit.
more
Similar to ‘less’ but only allows forward navigation. Press Space (or enter) to scroll down and ‘q’ to exit.
head
Displays the first 10 lines of a file by default. Use ‘head -n X file’ to specify a different number of lines.
tail
Displays the last 10 lines of a file by default. Useful for monitoring log files in real-time using ‘tail -f filename’.
mkdir
Creates a new directory. Syntax: ‘mkdir new_directory’. Use ‘mkdir -p parent/child’ to create nested directories.
cd
Changes the current directory. Use ‘cd ..’ to move up one level or ‘cd /path/to/directory’ to switch to a specific location.
rm
Deletes a file permanently. Use ‘rm -r directory’ to remove directories and their contents recursively.
rmdir
Removes an empty directory. If the directory contains files, you must use ‘rm -r’ instead.
mv
Moves or renames files and directories. Syntax: ‘mv old_name new_name’ or ‘mv file /new/location’.
man
Displays the manual page for a given command, providing detailed information on its usage and options. Example: ‘man ls’.
clear
Clears the terminal screen, removing all previous output but keeping the session active.
What is the general form that we follow when using chmod?
chmod xxx filename
where xxx is the permission
what base are setting permissions in?
octal (ex: 660)
What do the three octal digits represent?
the three permission groups:
* The first digits sets the permissions for the owner.
* The second digit sets the permissions for the group
* The third digit sets the permissions for others.
what does the string
-rw-rw—- mean?
beginning “-“ means file, if it were d it would be directory
*owner can read and write
*Group can read and write
*nobody can execute
*others cannot do anything
