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linux

File System​

Essential command binaries: /bin
System boot loader files: /boot
Device files: /dev
Host-specific system-wide configuration files: /etc
User home directory: /home
Shared library modules: /lib
Media file such as CD-ROM: /media
Temporary mounted filesystems: /mnt
Add-on application software packages
Automatically generated file system: /proc
Home directory for root user: /root
Run-time program data: /run
System binaries: /sbin
Site-specific data served by this system: /srv
Virtual directory providing information about the system: /sys
Temporary files: /tmp
Read-only user files: /usr
File that is expected to continuously change: /var

Cloudairy (2023-09-16 13:06:08)
#linux

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Reverse order by time​

a -> all
h -> human readable size
r -> reverse
t -> order by time

ls -lahrt

Unknown (2023-09-07 12:12:55)
#linux

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Kill all firefox processes​

pkill -f firefox

Unknown (2023-08-27 22:21:55)
#linux

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Delete user and home its home folder​

sudo userdel -r userName

Unknown (2023-08-27 22:21:12)
#linux

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User's UID​

id -u username

User's GID​

id -g username

https://kb.iu.edu/d/adwf

Unknown (2023-08-14 16:29:07)
#linux

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Multiple SSH Keys​

Using more than one ssh key, add below lines to this file: ~/.ssh/config

IdentityFile ~/Desktop/.ssh/id_rsa  
IdentityFile ~/.ssh/id_rsa

Unknown (2022-08-13 21:09:20)
#linux

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Change SSH port​

  • Find "# Listen 22" line and remove sharp in this file: /etc/ssh/sshd_config
  • Then change port number
  • Restart sshd service, logout, login

Source: https://www.howtoforge.com/how-to-install-gitlab-server-with-docker-on-ubuntu-1804/

Unknown (2022-08-13 21:09:32)
#linux

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  • To not keep track command history, write commands start with whitespace
  • Find duplicate lines in a filecat data.txt | sort | uniq -d
  • Write command(s) into "rc.local" to execute on boot
  • Delete history: history -c
  • Find anything: find / -iname "*.err”
  • Extract .rar files: unrar x -y [path]
  • netstat -ant -> Active Internet connections (including servers)
  • Delete files inside of a directory: rm -f dirName/*
  • Search a keyword and show 2 lines before/after grep -B 2 -A 2 keyword README.txt
  • watch -n 5 date run any command at regular intervals
  • $ echo '{"a":42, "b": {"x": 127}}' | python -mjson.tool
  • Detailed ls: ls -R
  • List whole files with relative paths: find /home/sample -type f
  • Website accessible? scutil -r web-site-name
  • Zip a file with password: zip -e destination.zip source-to-zip.txt
  • Find duplicates in a folder: fdupes -r .
  • exiftool -all:all file.pdf

Unknown (2022-08-13 21:04:29)
#linux