Add solutions for sort/uniq/head/tail exercises

- script-01.sh: sort scores-table.txt by name.
- script-02.sh: sort scores-table.txt by first score (numeric, descending).
- script-03.sh: show top 3 players by first score.
- script-04.sh: show the player with the second highest first score.
- script-05.sh: list unique events from events.txt.
- script-06.sh: count Entry/Exit occurrences in events.txt.
- script-07.sh: count Entry/Exit occurrences in events-with-timestamps.txt (skip header, sort by Event column, count Event values).

Author: Iswanna

shell-pipelines/sort-uniq-head-tail/script-01.sh

@@ -5,3 +5,5 @@ set -euo pipefail
 # The input for this script is the scores-table.txt file.
 # TODO: Write a command to output scores-table.txt, with lines sorted by the person's name.
 # The first line of your output should be "Ahmed London 1 10 4" (with no quotes). And the third line should be "Chandra Birmingham 12 6".
+
+sort ./scores-table.txt

shell-pipelines/sort-uniq-head-tail/script-02.sh

@@ -5,3 +5,5 @@ set -euo pipefail
 # The input for this script is the scores-table.txt file.
 # TODO: Write a command to output scores-table.txt, with lines sorted by the person's first score, descending.
 # The first line of your output should be "Basia London 22 9 6" (with no quotes).
+
+sort -k3 -nr ./scores-table.txt

shell-pipelines/sort-uniq-head-tail/script-03.sh

@@ -8,3 +8,5 @@ set -euo pipefail
 # Basia London 22 9 6
 # Piotr Glasgow 15 2 25 11 8
 # Chandra Birmingham 12 6
+
+sort -k3 -nr ./scores-table.txt | head -3

shell-pipelines/sort-uniq-head-tail/script-04.sh

@@ -5,3 +5,5 @@ set -euo pipefail
 # The input for this script is the scores-table.txt file.
 # TODO: Write a command to output scores-table.txt, with shows the line for the player whose first score was the second highest.
 # Your output should be: "Piotr Glasgow 15 2 25 11 8" (without quotes).
+
+sort -k3 -nr ./scores-table.txt | head -2 | tail -1

shell-pipelines/sort-uniq-head-tail/script-05.sh

@@ -6,3 +6,5 @@ set -euo pipefail
 # TODO: Write a command to show a list of all events that have happened, without duplication.
 # The order they're displayed doesn't matter, but we never want to see the same event listed twice.
 # Your output should contain 6 lines.
+
+sort ./events.txt | uniq

shell-pipelines/sort-uniq-head-tail/script-06.sh

@@ -5,3 +5,5 @@ set -euo pipefail
 # The input for this script is the events.txt file.
 # TODO: Write a command to show how many times anyone has entered and exited.
 # It should be clear from your script's output that there have been 5 Entry events and 4 Exit events.
+
+sort ./events.txt | uniq -c -w5

shell-pipelines/sort-uniq-head-tail/script-07.sh

@@ -6,3 +6,5 @@ set -euo pipefail
 # TODO: Write a command to show how many times anyone has entered and exited.
 # It should be clear from your script's output that there have been 5 Entry events and 4 Exit events.
 # The word "Event" should not appear in your script's output.
+
+tail -n +2 ./events-with-timestamps.txt | sort -k3,3 | uniq -c -f2 -w5