1. Supervise command (run every 2s)

watch "ls -larth"

2. Kill program using one port

sudo fuser -k 8000/tcp

3. Limit memory usage for following commands

ulimit -Sv 1000       # 1000 KBs = 1 MB
ulimit -Sv unlimited  # Remove limit

4. Rename selected files using a regular expression

rename 's/\.bak$/.txt/' *.bak

5. Get full path of file

readlink -f file.txt

6. List contents of tar.gz and extract only one file

tar tf file.tgz
tar xf file.tgz static

7. List files by size

ls -lS

8. Nice trace route

mtr google.com

9. Find files tips

find . -size 20c             # By file size (20 bytes)
find . -name "*.gz" -delete  # Delete files
find . -exec echo {} \;      # One file by line
./file1
./file2
./file3
find . -exec echo {} \+      # All in the same line
./file1 ./file2 ./file3

10. Print text ad infinitum

yes
yes hello

11. Who is logged in?

w

12. Prepend line number

ls | nl

13. Grep with Perl like syntax (allows chars like \t)

grep -P "\t"

14. Cat backwards (starting from the end)

tac file

15. Check permissions of each directory to a file

It is useful to detect permissions errors, for example when configuring a web server.

namei -l /path/to/file.txt

16. Run command every time a file is modified

while inotifywait -e close_write document.tex
do
    make
done

17. Copy to clipboard

cat file.txt | xclip -selection clipboard

18. Spell and grammar check in Latex

detex file.tex | diction -bs

You may need to install the following: sudo apt-get install diction texlive-extra-utils.

19. Check resources' usage of command

/usr/bin/time -v ls

20. Randomize lines in file

cat file.txt | sort -R
cat file.txt | sort -R | head  # Pick a random sambple

# Even better (suggested by xearl in Hacker news):

shuf file.txt

21. Keep program running after leaving SSH session

If the program doesn't need any interaction:

nohup ./script.sh &

If you need to enter some input manually and then want to leave:

./script.sh
<Type any input you want>
<Ctrl-Z>          # send process to sleep
jobs -l           # find out the job id
disown -h jobid   # disown job
bg                # continue running in the background

Of course, you can also use screen or tmux for this purpose.

22. Run a command for a limited time

timeout 10s ./script.sh

# Restart every 30 minutes

while true; do timeout 30m ./script.sh; done

23. Combine lines from two sorted files

comm file1 file2

Prints these three columns:

Lines unique to file1.
Lines unique to file2.
Lines both in file1 and file2.

With options -1, -2, -3, you can remove each of these columns.

24. Split long file in files with same number of lines

split -l LINES -d file.txt output_prefix

25. Flush swap partition

If a program eats too much memory, the swap can get filled with the rest of the memory and when you go back to normal, everything is slow. Just restart the swap partition to fix it:

sudo swapoff -a
sudo swapon -a

26. Fix ext4 file system with problems with its superblock

sudo fsck.ext4 -f -y /dev/sda1
sudo fsck.ext4 -v /dev/sda1
sudo mke2fs -n /dev/sda1
sudo e2fsck -n <first block number of previous list> /dev/sda1

27. Create empty file of given size

fallocate -l 1G test.img

28. Manipulate PDFs from the command line

To join, shuffle, select, etc. pdftk is a great tool:

pdftk *.pdf cat output all.pdf        # Join PDFs together
pdftk A=in.pdf cat A5 output out.pdf  # Extract page from PDF

You can also manipulate the content with cpdf:

cpdf -draft in.pdf -o out.pdf      # Remove images
cpdf -blacktext in.pdf -o out.pdf  # Convert all text to black color

29. Monitor the progress in terms of generated output

# Write random data, encode it in base64 and monitor how fast it is being sent to /dev/null

cat /dev/urandom | base64 | pv -lbri2 > /dev/null

# pv options:
#   -l,  lines
#   -b,  total counter
#   -r,  show rate
#   -i2, refresh every 2 seconds

30. Find packages that have a given file in Ubuntu

apt-file update
apt-file search dir/file.h

This Arcane scene : https://www.youtube.com/watch?v=bU15Tk3UZwc

It's like they made 0 effort censoring it correctly 💀

Kinda long to read : https://d-shoot.net/kagi.html

I used to but people behind are bastards so I don't give money to them anymore.

It made me think of how I use search engines and most of the time I go on the same websites so I try to avoid search engines.

I use Mojeek with their focus feature (it is like lenses of Kagi). If I really need a search engine I use Mojeek with no focus, but most of the time the results are not good enough so I give them a feedback and go back on Duckduckgo.

Discovered about rg recently and it is cool!

Never Gonna Give You Up just so it breaks the Internet.

Alien.

"Waow what the f-!"
"- DON'T KILL IT!"
*kills it* "- Sorry, you were saying?"

Still can't figure why they didn't kill it when they had opportunity. 😬

The smell of the freshly mown lawn. It smells so bad and I'm allergic so I guess this explains why I dislike how it smells.

While calling terrorists everyone who stands for Gaza and sending the police, which mutilated many people under Macron's regime, to interrupt protests.

Classic Macron.

Intersting how we can "undress any girl" but I have not seen a tool to "undress any boy" yet. 😐

I don't know what it says about people developing those tools. (I know, in fact)

Idk how you do guys, but I just make turns quickly on myself and I am fully dressed. The only part I can never remove is that green diamond-shaped thing above my head. If you know how to remove that, tell me.

Mine is really weird and hard to describe. I'll try to be concise. I close my eyes (no shit Sherlock) and I imagine faces of people. It can be someone close, a star of a TV show, anything. Then I change element of their face one by one (e.g. their eyes). And I keep going. And everytime the face changes enough I question myself "I know this person, who is this ?". And when I answer the question, the face is clearer (because I've put a name on the face so it is easier to imagine it and correct it) and I can go on again until I fall asleep.