updates for version 2.5

Author: learnbyexample

LICENSE

@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2023 Sundeep Agarwal
+Copyright (c) 2025 Sundeep Agarwal
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

README.md

@@ -1,6 +1,6 @@
 # CLI text processing with GNU awk
 
-Example based guide to mastering GNU awk. Visit https://youtu.be/KIa_EaYwGDI for a short video about the book.
+Learn GNU awk with hundreds of examples and exercises. Visit https://youtu.be/KIa_EaYwGDI for a short video about the book.
 
 <p align="center"><img src="./images/gawk_ls.png" alt="CLI text processing with GNU awk ebook cover image" /></p>
 
@@ -20,15 +20,14 @@ See [Version_changes.md](./Version_changes.md) to keep track of changes made to
     * https://learnbyexample.gumroad.com/l/gnu_awk
     * https://leanpub.com/gnu_awk
 * You can also get the book as part of these bundles:
-    * **All books bundle** bundle from https://learnbyexample.gumroad.com/l/all-books
-        * Includes all my programming books
-    * **Magical one-liners** bundle from https://learnbyexample.gumroad.com/l/oneliners or https://leanpub.com/b/oneliners
-    * **Awesome Regex** bundle from https://learnbyexample.gumroad.com/l/regex or https://leanpub.com/b/regex
+    * **All books bundle** bundle from https://leanpub.com/b/learnbyexample-all-books or https://learnbyexample.gumroad.com/l/all-books
+    * **Magical one-liners** bundle from https://leanpub.com/b/oneliners or https://learnbyexample.gumroad.com/l/oneliners
+    * **Awesome Regex** bundle from https://leanpub.com/b/regex or https://learnbyexample.gumroad.com/l/regex
 * See https://learnbyexample.github.io/books/ for a list of other books
 
 For a preview of the book, see [sample chapters](./sample_chapters/gnu_awk_sample.pdf).
 
-The book can also be [viewed as a single markdown file in this repo](./gnu_awk.md). See my blogpost on [generating pdfs from markdown using pandoc](https://learnbyexample.github.io/customizing-pandoc/) if you are interested in the ebook creation process.
+The book can also be [viewed as a single markdown file in this repo](./gnu_awk.md). See my blogpost on [generating pdf/epub from markdown using pandoc](https://learnbyexample.github.io/customizing-pandoc/) if you are interested in the ebook creation process.
 
 For the web version of the book, visit https://learnbyexample.github.io/learn_gnuawk/
 
@@ -95,11 +94,12 @@ You can reach me via:
 * [Warning](https://commons.wikimedia.org/wiki/File:Warning_icon.svg) and [Info](https://commons.wikimedia.org/wiki/File:Info_icon_002.svg) icons by [Amada44](https://commons.wikimedia.org/wiki/User:Amada44) under public domain
 * [arifmahmudrana](https://github.com/arifmahmudrana) for spotting an ambiguous explanation
 * [Pound-Hash](https://github.com/Pound-Hash) for critical feedback
+* [FabijanC](https://github.com/FabijanC) and [alexwheezy](https://github.com/alexwheezy) for spotting ambiguous descriptions, typos and issues with commands
 * [mdBook](https://github.com/rust-lang/mdBook) — for web version of the book
     * [mdBook-pagetoc](https://github.com/JorelAli/mdBook-pagetoc) — for adding table of contents for each chapter
     * [minify-html](https://github.com/wilsonzlin/minify-html) — for minifying html files
 
-Special thanks to all my friends and online acquaintances for their help, support and encouragement, especially during these difficult times.
+Special thanks to all my friends and online acquaintances for their help, support and encouragement, especially during difficult times.
 
 <br>
 

Version_changes.md

@@ -1,5 +1,14 @@
 <br>
 
+### 2.5
+
+* Command version updated to **GNU awk 5.3.1**
+* Added details for the `--csv` option and the `\u` escape sequence
+* Corrected typos, updated exercises, descriptions and external links
+* Updated Acknowledgements section
+
+<br>
+
 ### 2.0
 
 * Command version updated to **GNU awk 5.2.2**

code_snippets/Builtin_functions.sh

@@ -105,11 +105,11 @@ awk 'index($0, "a+b")==1' eqns.txt
 
 awk -v s="a+b" 'index($0, s)==length()-length(s)+1' eqns.txt
 
-echo 'a\b\c\d' | awk -v s='a\b' 'index($0, s)'
+printf '%s\n' 'a\b\c\d' | awk -v s='a\b' 'index($0, s)'
 
-echo 'a\b\c\d' | awk -v s='a\\b' 'index($0, s)'
+printf '%s\n' 'a\b\c\d' | awk -v s='a\\b' 'index($0, s)'
 
-echo 'a\b\c\d' | s='a\b' awk 'index($0, ENVIRON["s"])'
+printf '%s\n' 'a\b\c\d' | s='a\b' awk 'index($0, ENVIRON["s"])'
 
 ## system
 

code_snippets/Control_Structures.sh

@@ -8,7 +8,7 @@ seq 6 | awk '{ORS = NR%3 ? "-" : RS} 1'
 
 awk '/^b/{print; print($NF>0 ? "------" : "======")}' table.txt
 
-## loops
+## Loops
 
 awk 'BEGIN{for(i=2; i<7; i+=2) print i}'
 

code_snippets/Field_separators.sh

@@ -56,7 +56,7 @@ echo 'Sample123string42with777numbers' | awk -F'[0-9]+' '{print $2}'
 
 echo 'Sample123string42with777numbers' | awk -F'[a-zA-Z]+' '{print $2}'
 
-echo 'load;err_msg--\ant,r2..not' | awk -F'\\W+' '{print $3}'
+printf '%s\n' 'load;err_msg--\ant,r2..not' | awk -F'\\W+' '{print $3}'
 
 echo 'hi.bye.hello' | awk -F. '{print $2}'
 
@@ -122,17 +122,33 @@ s='items: "apple" and "mango"'
 
 echo "$s" | awk -v FPAT='"[^"]+"' '{print $1}'
 
+echo 'Read Eat Sleep' | awk -v FPAT='e' '{print NF}'
+
+echo 'Read Eat Sleep' | awk -v IGNORECASE=1 -v FPAT='e' '{print NF}'
+
+echo 'Read Eat Sleep' | awk -v IGNORECASE=1 -v FPAT='[e]' '{print NF}'
+
+## CSV processing with FPAT
+
 s='eagle,"fox,42",bee,frog'
 
 echo "$s" | awk -F, '{print $2}'
 
 echo "$s" | awk -v FPAT='"[^"]*"|[^,]*' '{print $2}'
 
-echo 'Read Eat Sleep' | awk -v FPAT='e' '{print NF}'
+## CSV processing with `--csv`
 
-echo 'Read Eat Sleep' | awk -v IGNORECASE=1 -v FPAT='e' '{print NF}'
+s='"toy,eagle\"s","fox,42",bee,frog'
 
-echo 'Read Eat Sleep' | awk -v IGNORECASE=1 -v FPAT='[e]' '{print NF}'
+printf '%b' "$s" | awk -v FPAT='"[^"]*"|[^,]*' '{print $2}'
+
+printf '%b' "$s" | awk -k '{print $2}'
+
+ printf '%b' "$s" | awk -k -v OFS=: '{$1=$1} 1'
+
+cat newline.csv
+
+awk -k 'NR==1{print $2}' newline.csv
 
 ## FIELDWIDTHS
 

code_snippets/Installation_and_Documentation.sh

@@ -1,10 +1,10 @@
 ## Installation
 
-wget https://ftp.gnu.org/gnu/gawk/gawk-5.2.2.tar.xz
+wget https://ftp.gnu.org/gnu/gawk/gawk-5.3.1.tar.xz
 
-tar -Jxf gawk-5.2.2.tar.xz
+tar -Jxf gawk-5.3.1.tar.xz
 
-cd gawk-5.2.2/
+cd gawk-5.3.1/
 
 ./configure
 

code_snippets/Regular_Expressions.sh

@@ -82,7 +82,7 @@ printf 'a^2 + b^2 - C*3\nd = c^2' | awk '/b\^2/'
 
 echo '(a*b) + c' | awk '{gsub(/\(|)/, "")} 1'
 
-echo '\learn\by\example' | awk '{gsub(/\\/, "/")} 1'
+printf '%s\n' '\learn\by\example' | awk '{gsub(/\\/, "/")} 1'
 
 ## Using string literal as a regexp
 
@@ -102,9 +102,9 @@ awk 'gsub("\\<par\\>", "X")' anchors.txt
 
 awk 'gsub(/\<par\>/, "X")' anchors.txt
 
-echo '\learn\by\example' | awk '{gsub("\\\\", "/")} 1'
+printf '%s\n' '\learn\by\example' | awk '{gsub("\\\\", "/")} 1'
 
-echo '\learn\by\example' | awk '{gsub(/\\/, "/")} 1'
+printf '%s\n' '\learn\by\example' | awk '{gsub(/\\/, "/")} 1'
 
 ## The dot meta character
 
@@ -202,15 +202,15 @@ echo 'I like "mango" and "guava"' | awk '{gsub(/"[^"]+"/, "X")} 1'
 
 printf 'tryst\nfun\nglyph\npity\nwhy\n' | awk '!/[aeiou]/'
 
-echo 'load;err_msg--\/ant,r2..not' | awk '{gsub(/\W+/, "|")} 1'
+printf '%s\n' 'load;err_msg--\/ant,r2..not' | awk '{gsub(/\W+/, "|")} 1'
 
 printf 'hi  \v\f  there.\thave   \ra nice\t\tday\n' | awk '{gsub(/\s+/, " ")} 1'
 
-echo 'w=y\x+9*3' | awk '{gsub(/[\w=]/, "")} 1'
+printf '%s\n' 'w=y\x+9*3' | awk '{gsub(/[\w=]/, "")} 1'
 
-echo '42\d123' | awk '{gsub(/\d+/, "-")} 1'
+printf '%s\n' '42\d123' | awk '{gsub(/\d+/, "-")} 1'
 
-echo '42\d123' | perl -pe 's/\d+/-/g'
+printf '%s\n' '42\d123' | perl -pe 's/\d+/-/g'
 
 ## Named character sets
 
@@ -260,7 +260,11 @@ echo 'hello world' | awk '{sub(/.*/, "[\x26]")} 1'
 
 echo 'read' | awk '{sub(/\d/, "l")} 1'
 
-## Replace specific occurrence
+awk 'BEGIN{print "\u3b1\u3bb\u3b5\u3c0\u3bf\u3cd"}'
+
+awk 'BEGIN{print "cag\u308" "ed"}'
+
+## Replace a specific occurrence
 
 s='apple:banana:cherry:fig:mango'
 
@@ -286,7 +290,7 @@ echo "$s" | awk '{print gensub(/(.*),((.*,){2})/, "\\1[]\\2", 1)}'
 
 s='effort flee facade oddball rat tool'
 
-echo "$s" | awk '{gsub(/\w*(\w)\1\w*/, "X")} 1'
+echo "$s" | awk '{print gensub(/\w*(\w)\1\w*/, "X", "g")}'
 
 echo "$s" | sed -E 's/\w*(\w)\1\w*/X/g'
 

example_files/newline.csv

@@ -0,0 +1,5 @@
+apple,"1
+2
+3",good
+fig,guava,"32
+54",nice