Sunday, June 17, 2018
Command Line basics
space commands take us to the end of an document
$cat can take two files separated by a space
nano full screen program. Mainly used to edit a file
Move is very powerful for moving files around and renaming them. Move is also very powerful for moving directories.
$mv within the same directory
mv filename1.txt filename2.txt is just like rename
if instead say
mv filename.txt documents/ it is just to move doc to new directory
dot is a short cut for the current directory
cp can leave the original file in place, just like copy.
cp hello.txt hi.txt
Can't just copy a directory, but need to copy recursively,
$cp -r sourcedirectoryname destination directoryname
$rm command is very dangerous via command console
make directory $mkdir
cannot recurse, creating nested directory lil document/notes/console
mkdir -p documents/notes/console/part_1
this chaining works for nested directories
Create User Managing Users
print out the name of the user
add a new user
$sudo adducer user_name
switch back to the previous user
or can use exit which stops the previous su command
rwx read write execute
ugo user group other
drwxrwxrwx d for directory, 9 permissions in ufo order
chmod change mode also changes permission
$ chmod o+w hello.txt
$ chmod o-w hello.txt
$ chmod +x hello.txt (add execution for everyone)
10 11 12 13
one eight one one
one eight two one
r = 4 w = 2 x =1
first digit = u
2nd digit = g
3rd digit = o
rwx = 7 --- = 0
r-x = 5, -w- = 2
e.g. chmod 751 hello.txt
File Owner Ship
$sudo chown username filename.txt
will be prompted for password
but with nano not able to write, only view after changing owner
CHANGING GROUP NAME
$sudo chown username:groupname filename.txt
CAN NOW MODIFY because username is the same as the owner. Before when looking at ano with a the old owner which no longer have write permission
a super user command, run as root super user without having to know the password etc, sudo grants permission to other users, will requires own password not the root user password,
$!! runs the previous command
When running nano which is a program, creates a process, which is a running instance of the program. There can be multiple instances.
task manager for processes, resources consumed like memory or CPU, process has an ID, owner,
question mark key brings up help function
e.g. sort the processes
capital F allows sorting
q to quit the program
Another program , will list out all the processes, represent running processes
(can see bash, and ps) ps is itself a program that creates a process, only in the current session
all process for user x, mean all processes for all users. it is not an interactive program. good for knowing what's running and what is the process ID. PID
Getting specific with piping, grep takes some input search for pattern only return lines with the pattern on it. This will also show up in its own ps search.
$ps aux | grep "top"
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