awk '
NR == 1         {HD = $1
#### Here we are putting condition NR==1 which means this will be TRUE in very first line of very first file only.
#### Where we are putting $1's value to variable HD. Actually we are creating headings here.
                }
#### FNR==1 is the condition which will be TRUE only when each file's first line will be read, as we all know variable FNR's value 
 #### will be reset each time it reads next file. Then we are using split, which is splitting the current Input_file's name putting it into an array
#### named T whose delimiter is "_". Now putting these values into variable named HD so HD will be something like Id Name E0_f0 at very first file, similarly it will concatenate the values of all Input_files.
FNR == 1        {split (FILENAME, T, "_")
                 HD = HD OFS $3 OFS $4 "_" T[2]
                }
#### creating a variable named IX here whose value is 1 less than FNR, then creating a variable named MAX(which is basically to know how many maximum lines are there in any Input_file)
#### So if MAX's value is already greater than variable IX then no change else replace the MAX's current value with IX's current value as it is greater than MAX.
                {IX  = FNR - 1
                 MAX = IX>MAX?IX:MAX
                }
#### FNR==NR(this condition will be TRUE only when very first file is being read), so creating an array named ID whose index is IX so it will be like...
#### ID[0]=Id, ID[1]=1 and so on.....
#### creating an array named NAME whose index is IX so it's value will be NAME[0]=Name, NAME[1]=N(,)'1 and so on...
FNR == NR       {ID[IX]   = $1
                 NAME[IX] = $3
                }
 #### So checking here condition if $1's value is equal to ID's value whose index is IX and $3's value is equal to NAME's value whose index is IX
#### Then we are creating an array named OUT with index IX and putting $3 and $4's values too to it. next will skip all further statements.
$1 == ID[IX] &&
$3 == NAME[IX]  {OUT[IX]  = OUT[IX] $3 OFS $4 OFS
                 next
                }
#### If above condition is NOT TRUE then it means there was NO match found for current IX and $1 or $3 values then we are adding a OFS space on that place so that it prints NULL(space) there.
                {OUT[IX]  = OUT[IX] OFS OFS
                }
#### So printing here value of HD(which is heading of all files), then going till maximum value of MAX(which is the number of maximum line in a file).
#### printing the values of ID and OUT then.
END             {print HD
                 for (i=1; i<=MAX; i++) print ID[i], OUT[i]
                }
#### Mentioning Output field separator as tab and mentioning all the files which needs to be passed to awk for reading.
' OFS="\t" A_*_pred.txt