Basic scripting is done

Bash-Scripting.txt

@@ -461,3 +461,202 @@
                                 |--------------------|
 
 
+-> For loops
+
+    for arg in [list]
+    do
+        command(s)..
+    done
+
+    * Example 
+        for PLANET in "Mercury Venus Earth"
+        do
+            echo $PLANET
+        done
+
+        for file in *.txt
+        do
+            $file
+        done
+
+-> For loops - C style for loops
+
+    for ((i=1; i <= 10 ; i++))
+    do
+        echo $i
+    done
+
+-> While loop
+
+    while [ condition ]
+    do
+        command(s)
+    done
+
+-> C-style While loop
+
+    while (( condition ))
+    do
+        command(s)
+    done
+
+    * Example
+        A=1
+        LIMIT=10
+        while (( A < LIMIT )) //no $ here
+        do
+            touch $A
+            let A++
+        done
+
+-> Reading Files with While loop
+
+    while read line
+    do
+        command(s)..
+    done < "$FILENAME"
+
+    cat "$FILENAME" |
+    while read line
+    do
+        echo $line
+    done
+
+-> Case:
+
+    case "$VAR" in
+
+        "$condition1")
+            command(s)...
+        ;;
+        "$condition2")
+            command(s)...
+        ;;
+        *)
+        command(s)..
+        ;;
+    esac
+
+    *Example:
+
+    case "$(whoami)" in
+
+     "root")
+            echo you are root
+            ;;
+     "richard"|"susan")
+            echo you are user
+            ;;
+     *)
+            echo I don't know you
+            ;;
+    esac
+
+-> shift 
+    It's a command to throw away the parameter count
+    that is given to the script.
+
+
+-> getopts:
+
+    * easy way how to parse short positional parameters (-f)
+    * doesn't support long positional parameters ( --help )
+    
+    * getopts optstring name
+
+    -> For examples:
+
+        #!/bin/bash
+
+        while getopts a:b:cd param; do
+         case $param in                                                     OPTIND is initialized to 1
+            a)  echo ""                                                     each time the shell or a
+                echo "parameter 'a' with argument: $OPTARG"                 shell script is invoked.
+                ;;
+            b)  echo "parameter 'b' with argument: $OPTARG"                 getopts places index of the
+                ;;                                                          next argument to be
+            c)  echo "parameter 'c' selected (no colon, no argument)"       processed into the variable
+                ;;                                                          OPTIND
+            d)  echo "parameter 'd' selected (no colon, no argument)"
+                ;;
+         esac
+        done
+
+
+-> getopt:
+
+    * parse command options (enhanced)
+
+    opts=`getopt -o a::b:cde --long file::,name::,help -- "$@"`
+    eval set -- "$opts"
+
+    #!/bin/bash
+
+    echo "All arguments: $@"
+    opts=`getopt -o a::b:cde --long file::,name:,help -- "$@"`
+    eval set -- "$opts"
+    echo "All arguments after getopt: $@"
+
+-> Arrays:
+
+    * Declaration
+        * ARRAY=(value1 value2 .. valueN)
+        * ARRAY=(one,two,three)
+
+    * Calling
+        * ${ARRAY[0]}   #one
+        * ${ARRAY[1]}   #two
+        * ${ARRAY[2]}   #three
+
+    
+    * ARRAY=(one,two,three)
+
+        ${ARRAY[0]}     #one
+        ${ARRAY[1]}     #two
+        ${ARRAY[2]}     #three
+        ${ARRAY[@]}     #all items in Arrays
+        ${ARRAY[*]}     #all items in array, delimited by first character of IFS
+        ${!ARRAY[@]}    #all indexes in the array ( @/* )
+        ${#ARRAY[@]}    #number of items in the array ( @/* )
+        ${#ARRAY[0]}    #length of item zero
+
+-> Functions
+
+    * function_name(){
+        <commands>
+      }
+
+    * function function_name{
+        <commands>
+      }
+
+    * Example
+        | function hello{
+        |     echo hello
+        | }
+        |
+        | echo "output from function hello: "
+        | hello
+
+
+
+        | function hello{
+        |     echo hello $1
+        |     return 11
+        | }
+        |
+        | echo "output from function hello: "
+        | hello richard
+        | echo "return value from function hello is: $?"
+
+
+
+        | function hello {                      function hello{
+        |   name=$1                                 local name=$1
+        |   echo "hello $name"                      echo "hello $name"
+        | }                                     }
+        |
+        | echo "enter your name:"               echo "enter your name:"
+        | read name     #richard                read name       #richard
+        | hello Peter   #hello Peter            hello Peter     #hello Peter
+        | echo $name    #Peter                  echo $name      #richard

array.sh

@@ -0,0 +1,17 @@
+#!/bin/bash
+
+ARRAY=($(ls *.txt))
+COUNT=0
+echo -e "FILE NAME \t WRITEABLE"
+for FILE in "${ARRAY[@]}"
+do
+    echo -n $FILE
+    echo -n "[${#ARRAY[$COUNT]}]"
+    if [ -w "$FILE" ]; then
+        echo -e "\t YES"
+    else
+        echo -e "\t NO"
+    fi
+
+    let COUNT++
+done

case.sh

@@ -0,0 +1,43 @@
+#!/bin/bash
+
+#read data from users and make them option to recheck
+#if provided data are correct
+
+echo -n "Enter your name: "
+read NAME
+echo -n "Enter your age: "
+read AGE
+echo -n "Enter your department: "
+read DEP
+
+echo "You've entered following: "
+echo "Name:             $NAME"
+echo "AGE:              $AGE"
+echo "Department:       $DEP"
+
+CHECK=0
+while [ $CHECK -eq 0 ]
+do
+
+    echo -n "Is that correct? [Y/n] "
+    read ANSWER
+
+    case "$ANSWER" in
+        "Y"|"y" )
+                echo "Name:         $NAME" >> empl.txt
+                echo "AGE:          $AGE"  >> empl.txt
+                echo "Department:   $DEP"  >> empl.txt
+                echo "================================" >> empl.txt
+                echo "Your data were saved into employee file"
+                CHECK=1
+                ;;
+        "N"|"n" )
+                echo "Nothing was saved, run the script again \
+if you want to add data to employee file"
+                CHECK=1
+                ;;
+        * )
+                echo "Wrong answer provided"
+    esac
+
+done

function.sh

@@ -0,0 +1,25 @@
+#!/bin/bash
+
+
+function addition {
+    local FIRST=$1
+    local SECOND=$2
+
+    let RESULT=FIRST+SECOND
+    echo "Result is: $RESULT"
+    let FIRST++
+    let SECOND++
+    return $RESULT
+}
+
+#do the addition of two numbers
+echo -n "Enter first number: "
+read FIRST
+echo -n "Enter second number: "
+read SECOND
+addition $FIRST $SECOND
+
+echo "RETURN: $?"
+echo "Printing variable:"
+echo "FIRST: $FIRST"
+echo "SECOND: $SECOND"

getopt.sh

@@ -0,0 +1,40 @@
+#!/bin/bash
+
+echo "All arguments: $@"
+
+opts=`getopt -o a::b:cde --long file::,name:,help -- "$@"`
+eval set -- "$opts"
+echo "All arguments after getopt: $@"
+
+while [ $# -gt 0 ]
+do
+    case "$1" in
+        -a) echo "parameter 'a' selected with argument: $2"
+            shift 2 #same of 2 shift command
+            ;;
+        -b) echo "parameter 'b' selected with argument: $2"
+            shift 2
+            ;;
+        -c) echo "paramter 'c' selected"
+            shift
+            ;;
+        -d) echo "paramter 'd' selected"
+            shift
+            ;;
+        -e) echo "paramter 'e' selected"
+            shift
+            ;;
+        --file) echo "parameter 'file' selected with argument: $2"
+                shift 2
+                ;;
+        --name) echo "parameter 'name' selected with argument: $2"
+                shift 2
+                ;;
+        --help) echo "parameter 'help' selected"
+                shift
+                ;;
+        *)      echo "something else: $1"
+                shift
+                ;;
+    esac
+done

getopts.sh

@@ -0,0 +1,15 @@
+#!/bin/bash
+
+while getopts a:b:cd param;
+do
+    case $param in
+        a) echo "parameter 'a' with argument: $OPTARG"
+            ;;
+        b) echo "parameter 'b' selected with argument: $OPTARG"
+            ;;
+        c) echo "parameter 'c' selected (no colon, no argument)"
+            ;;
+        d) echo "parameter 'd' selected"
+            ;;
+    esac
+done

print.sh

@@ -0,0 +1,25 @@
+#!/bin/bash
+
+#create script for printing files, which will display
+#also line numbers
+
+#argument check
+if [ $# -ne 1 ]; then
+    echo "Exactly one arugment is needed, run: $0 file-path"
+    exit 1
+fi
+
+#check if provided argument is a file
+if ! [ -f "$1" ]; then
+    echo "File you've specified doesn't exist"
+    exit 2
+fi
+
+FILENAME=$1
+COUNT=1
+
+while read line
+do
+    echo "$COUNT: $line"
+    let COUNT++
+done < "$FILENAME"

text.txt

@@ -0,0 +1,4 @@
+line 1
+line 2
+something 3
+something 4