Bitsized AWK

Learn AWK tweet by tweet

[Bitsized AWK @mawkic]

😎 TIL: ECMAScript / Javascript is influenced by AWK

You're welcome #javascript 🤪

[Bitsized AWK @mawkic]

@m_ou_se @spacekookie Do you still have the source?

More bookkeeping in AWK: 😋

https://t.co/GMSQ5Mgabz

[Bitsized AWK @mawkic]

📚 Weekend Read 📚

Many years ago, @WardCunningham has written a beautiful AWK script to calculate the expenses of their skip trip.

https://t.co/N8K6BVDFyx

💡 This is AWK at its best.

[Bitsized AWK @mawkic]

@bphogan Try AWK 😇

[Bitsized AWK @mawkic]

@gumnos 😎😄😄

[Bitsized AWK @mawkic]

😎 You agree, don't you? 😎

[podquotes @podquotesio]

"In terms of programming languages you get the most bang for the buck by learning AWK."
- Brian Kernighan

https://t.co/wbCMUbhBL6

[Bitsized AWK @mawkic]

🤓 How to print the first and the last line in a file? 🤓

awk 'NR==1; END{print}

[Bitsized AWK @mawkic]

🤔 Do you want to write better and portable AWK scripts?

Of course you want 😄

💡 GAWK (GNU AWK) supports --lint:

> awk --lint 'and($1,$2)' file.txt
awk: cmd. line:1: warning: `and' is a gawk extension

[Unix tool tip @UnixToolTip]

awk is the coolest tool you don’t know
https://t.co/8iJCNTUiNN

[Bitsized AWK @mawkic]

@gumnos Ha! Nice 👍

[Bitsized AWK @mawkic]

🤔 Do you find your scripts with all these $1, $2 etc unreadable? 🤔

💡 Try giving them names:

> docker ps | awk 'BEGIN{cont_id=1;image=2;}$image=="postgres"{print $cont_id}'

[Bitsized AWK @mawkic]

🤔 Is there an AWK script you don't understand? Post it here ⬇️

[Bitsized AWK @mawkic]

@UnixToolTip @jvlmdr And in case somebody wonders how this works: https://t.co/sFjn70Ecfg🤓

[Bitsized AWK @mawkic]

🤔 How to delete empty lines from a file? 🤔

awk NF file.txt

💡 NF is the number of fields. If the number of fields is 0, AWK does not print the line, but in all other cases, the line is just printed.

[Bitsized AWK @mawkic]

😎 While AWK does support if statements, patterns are often easier 💡

[Bitsized AWK @mawkic]

🤓 New week new trick! 🤓

🤔 Replace a string in AWK:

> awk '{gsub("bob", "anna")}1' file.txt

➡️ replace "bob" with "anna"
➡️ 1st param can be a regex (eg. /bob/)
➡️ 3rd param is optional (default $0 / line)

💡sed might be more suitable for such tasks 😉

[Bitsized AWK @mawkic]

How to print only odd lines 🤓

[Bitsized AWK @mawkic]

> awk 'NR%2 {print $1}' file.txt
anna
chad

👨‍🎨 This prints odd lines, because %2 (modulo 2) returns 0 if the NR is divisible by 2. Since 0 is false, those lines are not printed.
➡️ The block is easy: just print the first column

[Bitsized AWK @mawkic]

A third of the participants has known AWK for more than ten years 🤯

[Bitsized AWK @mawkic]

For how long have you known about AWK? #Linux #DevOps

[Bitsized AWK @mawkic]

For how long have you known about AWK? #Linux #DevOps

[Bitsized AWK @mawkic]

@sylv3on_ @TheCyberSecHub You're missing AWK 😉

[Bitsized AWK @mawkic]

🤔 Did you know you can write a self-contained AWK script? 🤔

➡️ Given a file:
> cat script.awk
#!/usr/bin/awk -f
{ print $0 }

➡️ Make it executable
> chmod +x script.awk

➡️ And run it
> ./script.awk file.txt

🐧 If only everything was so easy #Linux 🐧

[Bitsized AWK @mawkic]

😍 Last July, @lexfridman interviewed Brian Kernighan, one of the authors of AWK. Listen to Brian explaining why AWK is still very useful today.

https://t.co/2UndCrs8xO