Awk Program (10 lines of code) to extract the words from a text file and alphabetize them.

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# countWords.awk makes an alphabetical list of words in a text file with the frequecy of
#  occurrence of each word.
# Usage: gawk -f countWords.awk file.txt
###############################################################################################
BEGIN {
  while((getline l < ARGV[1])>0) {
    n=split(tolower(l),arr,"[^a-zA-Z]+")
    for(i=1; i<=n;i++)
      if(match(arr[i],"^[ \t\n]*$")<=0)
        if(arr[i] in freq) freq[arr[i]]++
        else freq[arr[i]]=1
  }
  k=0; for(v in freq) {k++; ind[k]=v}
  n=asort(ind)
  for(i=1;i<=n;i++) printf("%3d: name=%-20s  frequency=%3d\n",i,ind[i],freq[ind[i]])
}