Rename exercises dir

Name it instead "topics" so it won't be
strange if some topics included "exercises" directory.

exercises/shell/solutions/basic_date.md

@@ -1,13 +0,0 @@
-## Basic Date
-
-### Objectives
-
-1. Write a script that will put the current date in a file called "the_date.txt"
-
-### Solution
-
-```
-#!/usr/bin/env bash
-
-echo $(date) > the_date.txt
-```

exercises/shell/solutions/count_chars.md

@@ -1,24 +0,0 @@
-## Count Chars
-
-### Objectives
-
-1. Read input from the user until you get empty string
-2. For each of the lines you read, count the number of characters and print it
-
-### Constraints
-
-1. You must use a while loop
-2. Assume at least three lines of input
-
-### Solution
-
-```
-#!/usr/bin/env bash
-
-echo -n "Please insert your input: "
-
-while read line; do
-    echo -n "$line" | wc -c
-    echo -n "Please insert your input: "
-done
-```

exercises/shell/solutions/directories_comparison.md

@@ -1,30 +0,0 @@
-## Directories Comparison
-
-### Objectives
-
-1. You are given two directories as arguments and the output should be any difference between the two directories
-
-### Solution
-
-Suppose the name of the bash script is ```dirdiff.sh```
-
-```
-#!/bin/bash
-
-if test $# -ne 2
-then
-	echo -e "USAGE: ./dirdiff.sh directory1 directory2"
-	exit 1
-fi
-
-# check for the checksums. 
-# If both the checksums same, then both directories are same
-if test `ls -1 $1 | sort | md5sum | awk -F "  " '{print $1}'` == `ls -1 $2 | sort | md5sum | awk -F "  " '{print $1}'`
-then
-	echo -e "No difference between the 2 directories"
-	exit 0
-fi
-
-diff -q $1 $2
-
-```

exercises/shell/solutions/empty_files.md

@@ -1,20 +0,0 @@
-## Empty Files
-
-### Objectives
-
-1. Write a script to remove all the empty files in a given directory (including nested directories)
-
-### Solution
-
-```
-#! /bin/bash
-for x in *
-do
-    if [ -s $x ]
-    then
-        continue
-    else
-        rm -rf $x
-    fi
-done
-```

exercises/shell/solutions/factors.md

@@ -1,20 +0,0 @@
-## Shell Scripting - Factors
-
-### Objectives
-
-Write a script that when given a number, will:
-
-* Check if the number has 2 as factor, if yes it will print "one factor"
-* Check if the number has 3 as factor, if yes it will print "one factor...actually two!"
-* If none of them (2 and 3) is a factor, print the number itself
-
-### Solution
-
-```
-#!/usr/bin/env bash
-
-(( $1 % 2 )) || res="one factor"
-(( $1 % 3 )) || res+="...actually two!"
-
-echo ${res:-$1}
-```

exercises/shell/solutions/files_size.md

@@ -1,17 +0,0 @@
-## Files Size
-
-### Objectives
-
-1. Print the name and size of every file and directory in current path
-
-Note: use at least one for loop!
-
-### Solution
-
-```
-#!/usr/bin/env bash
-
-for i in $(ls -S1); do
-    echo $i: $(du -sh "$i" | cut -f1)
-done 
-```

exercises/shell/solutions/great_day.md

@@ -1,15 +0,0 @@
-## Great Day
-
-### Objectives
-
-1. Write a script that will print "Today is a great day!" unless it's given a day name and then it should print "Today is <given day>"
-
-Note: no need to check whether the given argument is actually a valid day
-
-### Solution
-
-```
-#!/usr/bin/env bash
-
-echo "Today is ${1:-a great day!}"
-```

exercises/shell/solutions/hello_world.md

@@ -1,15 +0,0 @@
-## Shell Scripting - Hello World
-
-### Objectives
-
-1. Define a variable with the string 'Hello World'
-2. Print the value of the variable you've defined and redirect the output to the file "amazing_output.txt"
-
-### Solution
-
-```
-#!/usr/bin/env bash
-
-HW_STR="Hello World"
-echo $HW_STR > amazing_output.txt
-```

exercises/shell/solutions/host_status.md

@@ -1,20 +0,0 @@
-## It's Alive!
-
-### Objectives
-
-1. Write a script to determine whether a given host is down or up
-
-### Solution
-
-```
-#!/usr/bin/env bash
-SERVERIP=<IP Address>
-NOTIFYEMAIL=test@example.com
-
-ping -c 3 $SERVERIP > /dev/null 2>&1
-if [ $? -ne 0 ]
-then
-   # Use mailer here:
-   mailx -s "Server $SERVERIP is down" -t "$NOTIFYEMAIL" < /dev/null
-fi
-```

exercises/shell/solutions/num_of_args.md

@@ -1,26 +0,0 @@
-## Number of Arguments
-
-### Objectives
-
-* Write a script that will print "Got it: <argument value>" in case of one argument
-* In case no arguments were provided, it will print "Usage: ./<program name> <argument>"
-* In case of more than one argument, print "hey hey...too many!"
-
-### Solution
-
-```
-#!/usr/bin/env bash
-
-set -eu
-
-main() {
-  case $# in
-    0) printf "%s" "Usage: ./<program name> <argument>"; return 1 ;;
-    1) printf "%s" "Got it: $1"; return 0 ;;
-    *) return 1 ;;
-  esac
-}
-
-main "$@"
-```
-

exercises/shell/solutions/sum.md

@@ -1,30 +0,0 @@
-## Sum
-
-### Objectives
-
-1. Write a script that gets two numbers and prints their sum
-3. Make sure the input is valid (= you got two numbers from the user)
-2. Test the script by running and passing it two numbers as arguments 
-
-### Constraints
-
-1. Use functions
-
-### Solution
-
-```
-#!/usr/bin/env bash
-
-re='^[0-9]+$'
-
-if ! [[ $1 =~ $re && $2 =~ $re ]]; then
-    echo "Oh no...I need two numbers"
-    exit 2
-fi
-
-function sum {
-    echo $(( $1 + $2 ))
-}
-
-sum $1 $2
-```