Shell Programming and Scripting

size=$(cat file* | wc -l)
cat file* | split -l $((size/4)) -

12|12345|09876
.
.
12|12345|78901

awk '
  BEGIN {
    n=4
    m=1
  }

  FNR==1 {
    if(NR>1) {
      A[m]+=sz
      f="outfile" m
      printf "%s",s>f
      m=1
      for(i=2; i<=n; i++)
        if(A[m]>A[i])
          m=i
      s=x
      sz=0
    }
  }

  {
    s=s $0 ORS
    sz+=length
  }

  END {
    if(NR>1)printf "%s",s>f
  }
' $(ls -drS file*)

awk '
  BEGIN {
    n=4                      # set number of buckets
    m=1                      # initialize emptiest bucket
  }

  FNR==1 {                   # if a new file is starting to be read (FNR is line number per file)
    if(NR>1) {               # if it is not the very first file (NR is total line number for all files)
      A[m]+=sz               # add the size of the previous file to the emptiest bucket
      f="outfile" m          # specify the bucket output file name
      printf "%s",s>f        # print to last file from memory to emptiest bucket file
      m=1                    # set emptiest bucket to 1
      for(i=2; i<=n; i++)    # for every the other bucket
        if(A[m]>A[i])        # if the minimum bucket is fuller then that bucket
          m=i                # make that bucket the new minimum
      s=x                    # clear the file memory
      sz=0                   # clear its size
    }
  }

  {
    s=s $0 ORS               # Add next line of file to memory
    sz+=length               # Add the number of characters on that line to the size
  }

  END {
    if(NR>1)printf "%s",s>f  # print the last file in memory to the emptiest bucket file
  }
' $(ls -drS file*)           # read the files in reverse sorted size order

awk: Cannot find or open file 16.
 The source line number is 4

12|09876|12345 78907|111.46|A|1234567
12|09876|12345 12345|111.46|A|1234567