Shell Programming and Scripting

An_A1_nnn_R1.txt;  An_A1_nnm_R1.txt;  An_A1_nnoo_R1.txt
An_A2_nnn_R1.txt;  An_A2_nnm_R1.txt;  An_A2_nno_R1.txt

..................
An_A900_nnn_R1.txt;  An_A900_nnm_R1.txt;  An_A900_nno_R1.txt

cat An_A1_nnn_R1.txt  An_A1_nnmm_R1.txt   An_A1_nnoo_R1.txt > An_A1.R1.txt

cat *.txt >> your_big_file.text

for i in {1..900}
       do 
                 cat *A$i*R1.txt > A$i.R1.txt
      done

cat *A${i}*R1.txt >> A${i}.R1.txt

for i in {1..900}
do 
  cat *_A$i_*_R1.txt >> A$i.R1.txt
done

for i in {1..900}
do 
  cat *_A$i_*_R1.txt > A$i.R1.txt
done

#!/bin/bash

for i in {1..900}
 do 

    #cat *A"$i"*R1* > A"$i".R1.txt
    #cat *A"$i"*R1* >> A"$i".R1.txt
    cat *A${i}*R1.txt >> A${i}.R1.txt

done