Shell Programming and Scripting

awk '{$1=$1}1' infile |   #If the file is about 150MB this pipe still will work?
awk '
BEGIN{
  header="Type Of Record|ChargeableDuration|DateForStartOfCharge|ExchangeIdentity|RecordSequenceNumber|TimeForStartOfCharge|TimeForStopOfCharge|GSMCallReferenceNumber|MSCAddress|OutgoingRoute|CalledPartyNumber|NetworkCallReference|CallingPartyNumber|IncomingRoute"
  print header
  m=split(header,H,"|")
}

$1!="BeginOfRecord"{ next} # I think this means, go to next record if $1 is not exactly to BeginOfRecord?

{
  F[1]=$7
  for(i=8;i<=NF;i++) {
    if($i==H[2])  F[2]=$(i+11)":"$(i+19)":"$(i+27)
    if($i==H[3])  F[3]=$(i+8)
    if($i==H[4])  F[4]=$(i+2)
    if($i==H[5])  F[5]=$(i+2)
    if($i==H[6])  F[6]=$(i+11)":"$(i+19)":"$(i+27)
    if($i==H[7])  F[7]=$(i+11)":"$(i+19)":"$(i+27)
    if($i==H[8])  F[8]=$(i+2)
    if($i==H[9])  F[9]=$(i+22)
    if($i==H[10]) F[10]=$(i+2)
    if($i==H[11]) F[11]=$(i+22)
    if($i==H[12]) F[12]=$(i+2)
    if($i==H[13]) F[13]=$(i+22)
    if($i==H[14]) F[14]=$(i+2)
  }
  $0=x  #What does it mean this statement?
  for(i=1;i<=m;i++){  # which is the value of m? I dont see it with a value assisned previously
    $i=F[i] #Here you assign the array values to each field to be printed in the output?
    delete F[i] #Delete array values for memory and speed issues or why?
  }
}1 # This "1" at the end is to print the operations established within the for loop?
' RS= OFS=\| # If the blocks were separated by some string like "*** End of block" or only one blank line, how would be RS? RS="*** End of block"? or RS=" "

delete F[i] #Delete array values for memory and speed issues or why?

awk '{$1=$1}1' inputfile | awk ' ...' RS= OFS=\| > output

Script.sh inputfile > output 

awk '{$1=$1}1' "$1" | awk ' ...' RS= OFS=\|

gsub(/^[ \t]*/, "", $0) # I'm inserting this after BEGIN {} 
gsub(/[ \t]*$/, "", $0) # I'm inserting this after BEGIN {}