Category: geeking

grex

Post author By kewl
Post date August 6, 2021
No Comments on grex

grex is a command-line tool and library for generating regular expressions from user-provided test cases: https://github.com/pemistahl/grex

Tags regex

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Bash scripting cheatsheet

Post author By kewl
Post date January 18, 2019
No Comments on Bash scripting cheatsheet

Variables · Functions · Interpolation · Brace expansions · Loops · Conditional execution · Command substitution · One-page guide to Bash scripting

Source: Bash scripting cheatsheet

Tags bash, howto, shell, UNIX

geeking

an amazing directory: /proc

Post author By kewl
Post date April 4, 2018
No Comments on an amazing directory: /proc

Tags Linux, proc

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Human Artificial Intelligence

Post author By kewl
Post date April 3, 2018
No Comments on Human Artificial Intelligence

On human feedback loops: https://t.co/KBNRCQeoGU

— Daniel Gross 💡 (@danielgross) March 9, 2018

Tags AI, human

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Want to Teach Kids to Code? Send ‘Em to a ‘Hack Jam’
100 Kids and their adults gathered last weekend in Los Angeles to learn how to program, how to think, and how to start making things. This is what happened and why.

Tags video

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Elapsed time in UNIX shell

Post author By kewl
Post date March 20, 2012
No Comments on Elapsed time in UNIX shell

The other day I had enough calculating the time so I just wrote this script:
cat > ~/bin/timediff #!/bin/sh if [ -z $2 ]; then echo "usage: $0 " echo echo "ex. $0 11:49 12:51" exit 1 fi


end=`date +%s -d"$2"`

start=`date +%s -d"$1"`
diff=$(($end-$start))
diff=$(($diff/60))

hours=$(($diff/60))

min=$(($diff%60))

# Prepend a 0 if minute <10

if [ ${#min} -eq 1 ]; then

        min=0$min

fi

echo "$hours:$min"

Of course, it works in some cases only. This one is fine:
$ sh ~/bin/timediff 11:49 12:51 1:02
Whereas this one will not work:
$ sh ~/bin/timediff 11:49 1:51 -9:-58

But the output is quite obvious.