lk/fundamentals/basics.md

94 lines
1.6 KiB
Markdown
Raw Normal View History

2020-01-02 00:04:35 +00:00
# Processes
Process id 1 is systemd. All other processes are child processes.
> ps -sH
This has every process on the system, and -H shows the hierarchy. This can be piped to less to view easily.
> ps -u ghost
Looking at processes spawned from user 'ghost'.
> ps -e --forest
Like tree, but more.
> ps -sfH
The fucking lot.
All of this is from /proc, which is a direct line to the kernel. Commands like `free', `top' et c. pulls from /proc.
# Top
In `top' we can take the pid and then press `k' in order to kill that process.
# check what's going on with qutebrowser
> ps aux | grep qutebrowser
# Check open ports
sudo netstat -tulpn
#Check that udev process
systemctl status udev
# Show net interface
> ip addr show
This can also take arguments, such as the name of an interface.
# Find
> find . -name 'bob cv'
Find file 'bob cv'
> find . -size +7G
Find files of 7Gig or more.
> find -name *hidden* -type l
Find a symbolic link containing 'hidden' in the name.
> find -name *txt -delete
Delete all files from here of the *txt type.
> find -type d -empty
Find empty directories.
> find . mtime 50
Find all file modified precisely 50 days ago. There's also:
* -mtime +20
* file modified more than 20 days ago.
* -atime -13
* file *accessed* less than 13 days ago.
* -cmin 20
* file *modified* 20 minutes ago.
* -mmin +70
* files modified more than 70 minutes ago.
# Logs
> cat /var/logs/auth.log | grep fail
# Files
> file example.txt
This shows info about a file.
# Further reading
[Hund](https://hund0b1.gitlab.io/2019/02/11/a-collection-of-handy-ways-of-manipulating-text-in-bash.html) has some fantastic examples.