Notices by Yes, I Know IT ! 🎓 (yesiknowit@mastodon.social), page 10

In a #sed substitution pattern, you can use any character as a separator instead of /
Useful for path or urls:
s!/usr/local!/opt!

#Linux #UNIX

From a POSIX shell `$OLDPWD` holds the name of the previous working directory:
cd /tmp
echo You are here: $PWD
echo You were here: $OLDPWD
cd $OLDPWD

#Unix #Linux #Shell #cd

When using the find command, use `-iname` instead of `-name` for case-insensitive search
#Unix #Linux #Shell #Find

If you ever had to connect to an Oracle backend, you may know how painful it used to be to set up an Oracle Instance on your test/dev host.

Thanks to @Docker, it is now several orders of magnitude simpler!

https://www.yesik.it/EP18

#Oracle #Database
#Docker #Container
#Linux
#YesIKnowIT

If you don't know what is #Awk or how it could help you processing text files, then you NEED that little introduction:
https://youtu.be/PUYS6MO4p7Y

#Linux #Shell #AWK
#YesIKnowIT

@clacke Sometimes you write a long commit message, then realize you forgot something but don't want to clear the entire text to abort the commit

Centering text on 80 columns with stars:
sed -E ':x
s/^.{,80}$/*&/
s/^.{,80}$/&*/
tx
' file

#Shell #Sed #Linux

Delete all but the last line of a file:
sed -n '$p' file

#Shell #Sed #Linux

Display all user accounts separated by a colon in one very long line

cut -d: -f1 /etc/passwd | paste -s -d:

#Paste #Cut #Linux #Unix #POSIX #Utility

In the Bash, `~-` is expanded to the content of `OLDPWD`. So:

cd ~-/..

is a shortcut for the 2 commands:

cd "$OLDPWD" (or `cd -`)
cd ..

#Bash #Shell

Merging files on a line-by-line basis with the `paste` utility
https://yesik.it/EP23

#Paste #POSIX #Utility #Linux #Unix #Shell

Find words starting with `lin` (according to `/usr/share/dict/words`):

```
look lin
```

#Linux #Look #Utility

Poor's (wo)man stopwatch in your shell:

```
time read
```

#Linux #Shell #Stopwatch

Display a 2x3 matrix:

seq 6 | paste - - -

#Paste #Shell #Linux #Unix #POSIX #Utility

vlc -Idummy -Vcaca "Star Wars: Episode IV - A New Hope (1977).mkv"

Play #StarWars as it was originally intended by @GeorgeLucasILM back in the 70s

#VLC #AsciiArt #Linux #CommandLine

Split a fixed-width or delimited text file into individual columns using the `cut` command
https://yesik.it/EP22

#Cut #POSIX #Utility #Linux #Unix #Shell

`split` and `csplit`. Old friends, I used them a lot in the 1.44MB floppy disk era...

https://www.linux.com/learn/intro-to-linux/2017/8/splitting-and-re-assembling-files-linux
by Carla Schroder (https://twitter.com/CarlaSchroder)

A byte is, and always was, an 8 bits quantity!

No.

https://www.yesik.it/blog/2018-bit-nibble-byte-and-word

#Bit #Byte #Octet #Nibble #Word
#BinaryArithmetic #BooleanAlgebra
#ComputerScience #ComputerHistory

Do you want to run a Windows software on Linux? Or optimize your costs by running several virtual servers on the same hardware? In those cases, like in many other ones, virtualization is the technology to leverage.

But with so many different virtualization technologies readily available today, which one is the best for YOUR needs?
https://yesik.it/VIRT101
#VM #Containers #Emulation #Wine #CheatSheet

http://www.ostechnix.com/4-easy-ways-to-generate-a-strong-password-in-linux/

My preferred :
openssl rand 14 -base64
gpg --gen-random --armor 1 14

... but the passwords are not easy to remember. A good argument to use a password manager.
#password #linux #gpg #openssl