Shell Programming and Scripting

awk '{Q=$1}     #### Assigning $1's value to a variable named Q here.
 ($1 in A)      #### Checking if $1(first field) is already present in array A, if yes then execute following statements.)
{$1=X}          #### Nullifying the values of $1 here.
{A[Q]=A[Q]      #### Here I am concatenating or assigning the values to array A whose index is variable Q's value(which is $1).
?               #### When a condition provided before =(equal sign) gets TURE so statements after ? should get executed.
A[Q] s1 $0      #### So if condition is TRUE(which is here A[Q] means if value of array A whose index is Q is already present) so I am concatenating the values of A[Q] s1 and current line($0) here s1=, which I had mentioned into last before calling Input_file.
:               #### If above mentioned condition gets FALSE(means no value of A[Q] is present yet) then do following.
$0}             #### Assign array A's value with index Q to $0(current line).
END{            #### Starting END block here.
for(i in A){    #### Starting a for loop which will traverse inside array A(to fetch it's all values).
print A[i]}}    #### printing the values of array A whose index is i(a variable whose value is getting assigned while traversing in for loop).
' s1=","        #### Providing the value of variable named s1 to ,(As mentioned above too).
Input_file      #### Mentioning Input_file here.

awk '$1 != LAST {printf "%s%s", DL, $1; LAST = $1; DL = RS} {printf ",%s", $2} END {print _}' FS=, file
jvm01, Web 2.0 Feature Pack Library, IBM WebSphere JAX-RS, Custom01 Shared Library
jvm02, Web 2.0 Feature Pack Library, IBM WebSphere JAX-RS
jvm03, Web 2.0 Feature Pack Library, IBM WebSphere JAX-RS, Custom03 Shared Library