updates for version 2.1

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

@@ -1,10 +1,10 @@
 # CLI text processing with GNU sed
 
-Example based guide to mastering GNU sed. Visit https://youtu.be/nvKyKoeiZD8 for a short video about the book.
+Learn GNU sed with hundreds of examples and exercises. Visit https://youtu.be/nvKyKoeiZD8 for a short video about the book.
 
 <p align="center"><img src="./images/sed_ls.png" alt="CLI text processing with GNU sed ebook cover image" /></p>
 
-The book also includes exercises to test your understanding, which are presented together as a single file in this repo — [Exercises.md](./exercises/Exercises.md)
+The book also includes exercises to test your understanding, which are presented together as a single file in this repo — [Exercises.md](./exercises/Exercises.md).
 
 For solutions to the exercises, see [Exercise_solutions.md](./exercises/Exercise_solutions.md).
 
@@ -20,15 +20,15 @@ See [Version_changes.md](./Version_changes.md) to keep track of changes made to
     * https://learnbyexample.gumroad.com/l/gnu_sed
     * https://leanpub.com/gnu_sed
 * 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
+    * **Linux CLI Text Processing** bundle from https://leanpub.com/b/linux-cli-text-processing or https://learnbyexample.gumroad.com/l/linux-cli-text-processing
+    * **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_sed_sample.pdf).
 
-The book can also be [viewed as a single markdown file in this repo](./gnu_sed.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_sed.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_gnused/
 

Version_changes.md

@@ -1,5 +1,12 @@
 <br>
 
+### 2.1
+
+* Corrected typos, updated exercises, descriptions and external links
+* Updated snapshot image for the interactive TUI app
+
+<br>
+
 ### 2.0
 
 * Command version updated to **GNU sed 4.9**

code_snippets/BRE_ERE_Regular_Expressions.sh

@@ -194,15 +194,15 @@ printf 'tryst\nfun\nglyph\npity\nwhy\n' | sed '/[aeiou]/d'
 
 ## Escape sequence sets
 
-echo 'load;err_msg--\nant,r2..not' | sed -E 's/\W+/-/g'
+printf '%s\n' 'load;err_msg--\nant,r2..not' | sed -E 's/\W+/-/g'
 
 printf 'hi  \v\f  there.\thave   \ra nice\t\tday\n' | sed -E 's/\s+/ /g'
 
-echo 'w=y\x+9*3' | sed 's/[\w=]//g'
+printf '%s\n' 'w=y\x+9*3' | sed 's/[\w=]//g'
 
-echo '42\d123' | sed -E 's/\d+/-/g'
+printf '%s\n' '42\d123' | sed -E 's/\d+/-/g'
 
-echo '42\d123' | perl -pe 's/\d+/-/g'
+printf '%s\n' '42\d123' | perl -pe 's/\d+/-/g'
 
 ## Named character sets
 
@@ -252,7 +252,7 @@ echo 'hello world' | sed 's/.*/"\x26"/'
 
 echo 'effort flee facade oddball rat tool' | sed -E 's/\w*(\w)\1\w*/X/g'
 
-echo '\[\] and \\w and \[a-zA-Z0-9\_\]' | sed -E 's/(\\?)\\/\1/g'
+printf '%s\n' '\[\] and \\w and \[a-zA-Z0-9\_\]' | sed -E 's/(\\?)\\/\1/g'
 
 echo 'aa a a a 42 f_1 f_1 f_13.14' | sed -E 's/\b(\w+)( \1)+\b/\1/g'
 

code_snippets/Shell_substitutions.sh

@@ -40,13 +40,13 @@ s='{[(\ta^b/d).*+?^$|]}'
 
 s=$(printf '%s' "$s" | sed 's#[{[()^$*?+.\|/]#\\&#g')
 
-echo 'f*{[(\ta^b/d).*+?^$|]} - 3' | sed -E 's/'"$s"'/'"$r"'/g'
+printf '%s\n' 'f*{[(\ta^b/d).*+?^$|]} - 3' | sed -E 's/'"$s"'/'"$r"'/g'
 
 s='{[(\ta^b/d).*+?^$|]}'
 
 s=$(printf '%s' "$s" | sed 's#[[^$*.\/]#\\&#g')
 
-echo 'f*{[(\ta^b/d).*+?^$|]} - 3' | sed 's/'"$s"'/'"$r"'/g'
+printf '%s\n' 'f*{[(\ta^b/d).*+?^$|]} - 3' | sed 's/'"$s"'/'"$r"'/g'
 
 ## Command substitution
 

exercises/Exercise_solutions.md

@@ -428,7 +428,7 @@ eqn2 = pressure*3+8-14256
 * `*` is same as `{0,}`
 * `+` is same as `{1,}`
 
-**10)** True or False? In ERE, `(a*|b*)` is same as `(a|b)*`.
+**10)** In ERE, `(a*|b*)` is same as `(a|b)*` — True or False?
 
 False. Because `(a*|b*)` will match only sequences like `a`, `aaa`, `bb`, `bbbbbbbb`. But `(a|b)*` can match a mixed sequence like `ababbba` too.
 
@@ -508,7 +508,7 @@ $ echo 'apple42:fig100' | sed -E 's/^a\w+([0-9]+:fig)?/[&]/'
 [apple42:fig]100
 ```
 
-For patterns matching from the same starting location, longest match wins in case of BRE/ERE flavors. So, `\w+` will give up characters to allow `([0-9]+:fig)?` to also match in the second case. In other flavors like PCRE, `apple42` will be matched both the cases.
+For patterns matching from the same starting location, longest match wins in case of BRE/ERE flavors. So, `\w+` will give up characters to allow `([0-9]+:fig)?` to also match in the second case. In other flavors like PCRE, `apple42` will be matched for both the cases.
 
 **17)** For the input file `patterns.txt`, display lines starting with `4` or `-` or `u` or `sub` or `care`.
 
@@ -697,7 +697,7 @@ hi there
 bye
 ```
 
-**8)** For the input file `patterns.txt`, replace the last but second `ar` with `X`. Display only the modified lines.
+**8)** For the input file `patterns.txt`, filter lines containing three or more occurrences of `ar`. For such lines, replace the third from last occurrence of `ar` with `X`.
 
 ```bash
 $ sed -nE 's/(.*)ar((.*ar){2})/\1X\2/p' patterns.txt
@@ -1065,7 +1065,7 @@ $ sed -n '/^%%Code: python%%$/,/^%%end%%$/{//!p; /^%%end%%$/q}' code.txt
 3
 ```
 
-**4)** For the input file `broken.txt`, display lines between the markers `top` and `bottom`. The first `sed` command shown below doesn't work because lines till the end of file are printed when the second address isn't found.
+**4)** The input file `broken.txt` starts with a line containing `top` followed by some content before a line containing `bottom` is found. Blocks of lines bounded by these two markers repeats except for the last block as it is missing the `bottom` marker. The first `sed` command shown below doesn't work because it is matching till the end of file due to the missing marker. Correct this command to get the expected output shown below.
 
 ```bash
 $ cat broken.txt

exercises/Exercises.md

@@ -415,7 +415,7 @@ eqn2 = pressure*3+8-14256
 * `*` is same as
 * `+` is same as
 
-**10)** True or False? In ERE, `(a*|b*)` is same as `(a|b)*`.
+**10)** In ERE, `(a*|b*)` is same as `(a|b)*` — True or False?
 
 **11)** For the input file `patterns.txt`, construct two different REGEXPs to get the outputs as shown below. Display only the modified lines.
 
@@ -658,7 +658,7 @@ hi there
 bye
 ```
 
-**8)** For the input file `patterns.txt`, replace the last but second `ar` with `X`. Display only the modified lines.
+**8)** For the input file `patterns.txt`, filter lines containing three or more occurrences of `ar`. For such lines, replace the third from last occurrence of `ar` with `X`.
 
 ```bash
 $ sed ##### add your solution here
@@ -1019,7 +1019,7 @@ $ sed ##### add your solution here
 3
 ```
 
-**4)** For the input file `broken.txt`, display lines between the markers `top` and `bottom`. The first `sed` command shown below doesn't work because lines till the end of file are printed when the second address isn't found.
+**4)** The input file `broken.txt` starts with a line containing `top` followed by some content before a line containing `bottom` is found. Blocks of lines bounded by these two markers repeats except for the last block as it is missing the `bottom` marker. The first `sed` command shown below doesn't work because it is matching till the end of file due to the missing marker. Correct this command to get the expected output shown below.
 
 ```bash
 $ cat broken.txt