Merge pull request #8343 from srzamfir/feature/BAEL-3370_Guide_to_read_command

BAEL-3370 Guide to read command

linux-bash/read/src/main/bash/file.csv

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+car,car model,car year,car vin;Mercury,Grand Marquis,2000,2G61S5S33F9986032;Mitsubishi,Truck,1995,SCFFDABE1CG137362;Ford,Mustang,1968,2G4WS55J351278031;Ford,Crown Victoria,1996,4T1BK1EB8EU586249;GMC,Envoy,2004,WVGEF9BP3FD720618;

linux-bash/read/src/main/bash/read_inputs.sh

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+#!/bin/bash
+
+# section 2.1
+default_read(){
+    read input1 input2 input3
+    echo "[$input1] [$input2] [$input3]"
+}
+
+# section 2.2
+custom_ifs_no_array(){
+    OLDIFS=$IFS
+    IFS=";"
+    read input1 input2 input3
+    echo "[$input1] [$input2] [$input3]"
+    # restore default IFS after we're finished so current shell behaves like before
+    IFS=$OLDIFS
+}
+
+# Section 2.3
+prompt_read_password(){
+    prompt="You shall not pass:"
+    read -p "$prompt" -s input
+    echo -e "\ninput password [$input]"
+}
+
+array_read(){
+    declare -a input_array
+    text="baeldung is a cool tech site"
+    read -e -i "$text" -a input_array 
+    for input in ${input_array[@]} 
+        do
+            echo " word [$input]"
+        done
+}
+
+# section 3.1
+file_read(){
+    exec {file_descriptor}<"./file.csv"
+    declare -a input_array
+    delimiter=";"
+    while IFS="," read -a input_array -d $delimiter -u $file_descriptor 
+        do
+            echo "${input_array[0]},${input_array[2]}" 
+        done
+    exec {file_descriptor}>&-
+}
+
+# section 3.2
+command_pipe(){
+    ls -ll / | { declare -a input
+               read
+               while read -a input; 
+               do
+                   echo "${input[0]} ${input[8]}"
+               done }
+}
+
+# section 3.3
+timeout_input_read(){
+    prompt="You shall not pass:"
+    read -p "$prompt" -s -r -t 5 input
+        if [ -z "$input" ]; then
+            echo -e "\ntimeout occured!"
+        else
+            echo -e "\ninput word [$input]"
+        fi
+}
+
+exactly_n_read(){
+    prompt="Reading exactly 11 chars:"
+    read -p "$prompt" -N 11 -t 5 input1 input2 
+    echo -e "\ninput word1 [$input1]"
+    echo "input word2 [$input2]"
+}
+
+# main menu entry point
+echo "****Read command samples menu*****"
+PS3="Your choice (1,2,3 etc.):"
+options=("default_read" "custom_ifs_no_array" "prompt_read_password" \
+         "array_read" "file_read" "command_pipe" "timeout_input_read" \
+         "exactly_n_read" "quit")
+select option in "${options[@]}"
+do
+  case $option in
+        "default_read")
+            echo "Enter something separated by spaces"
+            default_read
+            ;;
+        "custom_ifs_no_array")  
+            echo "Enter something separated by ;"
+            custom_ifs_no_array
+            ;;
+        "prompt_read_password")
+            echo "Enter an invisible password after the prompt"
+            prompt_read_password
+            ;;
+        "array_read")
+            echo "Enter something else or just return"
+            array_read
+            ;;
+        "file_read")
+            echo "Reading from one liner csv file"
+            file_read
+            ;;
+        "command_pipe")
+            echo "Listing files and access rights from /"
+            command_pipe
+            ;;
+        "timeout_input_read")
+            echo "Enter something in 5 seconds or less"
+            timeout_input_read
+            ;;
+        "exactly_n_read")
+            echo "Enter at least 11 characters or wait 5 seconds"
+            exactly_n_read
+            ;;
+        "quit")
+            break
+            ;;
+        *) echo "Invalid option";;
+  esac
+done