Answers added for challenges called 'Tail of a Text File #2', ''Tr' Command #1', ''Tr' Command #2' and ''Tr' Command #3'.

Author: xChivalrouSx

linux-shell/00020_HackerrankLinuxShell.sh

@@ -3,4 +3,7 @@
 # Head of a Text File #1
 # https://www.hackerrank.com/challenges/text-processing-head-1/problem?isFullScreen=true
 
-head -n20 
+while read -r line;
+do
+    echo "$line" | head -n20
+done

linux-shell/00021_HackerrankLinuxShell.sh

@@ -3,4 +3,7 @@
 # Head of a Text File #2
 # https://www.hackerrank.com/challenges/text-processing-head-2/problem?isFullScreen=true
 
-head -c20 
+while read -r line;
+do
+    echo "$line" | head -c20 
+done

linux-shell/00022_HackerrankLinuxShell.sh

@@ -3,4 +3,7 @@
 # Middle of a Text File
 # https://www.hackerrank.com/challenges/text-processing-in-linux---the-middle-of-a-text-file/problem?isFullScreen=true
 
-head -22 | tail -11
+while read -r line;
+do
+    echo "$line" | head -22 | tail -11
+done

linux-shell/00023_HackerrankLinuxShell.sh

@@ -3,4 +3,7 @@
 # Tail of a Text File #1
 # https://www.hackerrank.com/challenges/text-processing-tail-1/problem?isFullScreen=true
 
-tail -20
+while read -r line;
+do
+    echo "$line" | tail -20
+done

linux-shell/00024_HackerrankLinuxShell.sh

@@ -0,0 +1,9 @@
+#!/bin/sh
+
+# Tail of a Text File #2
+# https://www.hackerrank.com/challenges/text-processing-tail-2/problem?isFullScreen=true
+
+while read -r line;
+do
+    echo "$line" | tail -c20
+done

linux-shell/00025_HackerrankLinuxShell.sh

@@ -0,0 +1,9 @@
+#!/bin/sh
+
+# 'Tr' Command #1
+# https://www.hackerrank.com/challenges/text-processing-tr-1/problem?isFullScreen=true
+
+while read -r line;
+do
+    echo "$line" | tr "(" "[" | tr ")" "]"
+done

linux-shell/00026_HackerrankLinuxShell.sh

@@ -0,0 +1,9 @@
+#!/bin/sh
+
+# 'Tr' Command #2
+# https://www.hackerrank.com/challenges/text-processing-tr-2/problem?isFullScreen=true
+
+while read -r line;
+do
+    echo "$line" | tr -d "[a-z]"
+done

linux-shell/00027_HackerrankLinuxShell.sh

@@ -0,0 +1,9 @@
+#!/bin/sh
+
+# 'Tr' Command #3
+# https://www.hackerrank.com/challenges/text-processing-tr-3/problem?isFullScreen=true
+
+while read -r line;
+do
+    echo "$line" | tr -s ' '
+done

linux-shell/README.md

@@ -22,4 +22,8 @@
 | 020 | [Head of a Text File #1](https://www.hackerrank.com/challenges/text-processing-head-1/problem?isFullScreen=true) | [00020_HackerrankLinuxShell](./00020_HackerrankLinuxShell.sh) |
 | 021 | [Head of a Text File #2](https://www.hackerrank.com/challenges/text-processing-head-2/problem?isFullScreen=true) | [00021_HackerrankLinuxShell](./00021_HackerrankLinuxShell.sh) |
 | 022 | [Middle of a Text File](https://www.hackerrank.com/challenges/text-processing-in-linux---the-middle-of-a-text-file/problem?isFullScreen=true) | [00022_HackerrankLinuxShell](./00022_HackerrankLinuxShell.sh) |
-| 023 | [Tail of a Text File #1](https://www.hackerrank.com/challenges/text-processing-tail-1/problem?isFullScreen=true) | [00023_HackerrankLinuxShell](./00023_HackerrankLinuxShell.sh) |
+| 023 | [Tail of a Text File #1](https://www.hackerrank.com/challenges/text-processing-tail-1/problem?isFullScreen=true) | [00023_HackerrankLinuxShell](./00023_HackerrankLinuxShell.sh) |
+| 024 | [Tail of a Text File #2](https://www.hackerrank.com/challenges/text-processing-tail-2/problem?isFullScreen=true) | [00024_HackerrankLinuxShell](./00024_HackerrankLinuxShell.sh) |
+| 025 | ['Tr' Command #1](https://www.hackerrank.com/challenges/text-processing-tr-1/problem?isFullScreen=true) | [00025_HackerrankLinuxShell](./00025_HackerrankLinuxShell.sh) |
+| 026 | ['Tr' Command #2](https://www.hackerrank.com/challenges/text-processing-tr-2/problem?isFullScreen=true) | [00026_HackerrankLinuxShell](./00026_HackerrankLinuxShell.sh) |
+| 026 | ['Tr' Command #3](https://www.hackerrank.com/challenges/text-processing-tr-3/problem?isFullScreen=true) | [00027_HackerrankLinuxShell](./00027_HackerrankLinuxShell.sh) |