Wednesday, 5 September 2012

A Linux one-liner to find all the acronyms in your Latex files

At the beginning of my PhD thesis, I include a List of Acronyms. Of course, I would like to be sure that my list is comprehensive. I don't want any strange acronyms to appear in the text of my thesis, without first appearing in my list of acronyms. But how can I easily identify all of the acronyms in the Latex source, without having to read all 244 pages manually?

grep to the rescue, again

Like most other areas of my life, this problem can be easily solved with a Linux one-liner centered around grep:

cat *.tex | grep -wo "[A-Z]\+\{2,10\}" | sort | uniq -c | sort -gr

Let's take a look at the pipeline:
  • The cat *.tex outputs all my Latex to standard output.
  • The grep -wo  "[A-Z]\+\{2,10\}" matches whole words (the -w flag) that contain between 2 and 10 upper case letters. The -o flag returns only the match, not the entire line.
  • The first sort sorts the acronyms, which is useful for the next step.
  • The uniq gets rid of duplicates, but retains a counter because of the -c flag.
  • Finally, the second sort sorts the entries numerically (-g) and reverses the results (-r).

  • Here's the output on my thesis:

        292 IR
        241 LDA
        166 LSI
        125 VSM
         87 TCP
         80 EM
         35 APFD
         34 SUT
         29 HSD
         22 TOPIC
         22 II
         18 MALLET
         16 LOC
         14 PS
         14 OR
         14 IDE
         12 CALLG
         11 ICA
         10 RNDM
         10 MAP
         10 KL
         10 CS

Note that this command works with any text file; it is not unique to Latex. Just change the cat command.


  1. Hi Stephen,

    Two questions.

    1- There are some acronyms like "QoS" (quality of Service) having a combination of uppercase and lowercase together. How I can change your command to detect such acronyms as well.

    2- what are the numbers coming in left hand side of the acronyms.

    PS: it seems that some words written in uppercase are included in the list.


    1. I changed the command to

      cat *.tex | grep -wo "[A-Zo-]\+\{2,5\}" | sort | uniq -c | sort -gr


    2. Homayoun,

      Thanks for your reply.

      Your command doesn't quite work. It only allows the lowercase letter to be 'o', and does not require any following characters to be uppercase, and in fact does require the first character to be uppercase either. Hence, 'Qoo' would match, so would 'oN'. To allow for any lowercase characters in the middle of the word (but still requiring uppercase characters at least as the first and last character of the word), you can try:

      cat *.tex | grep -wo "[A-Z]\+[a-z]*[A-Z]\+" | sort | uniq -c | sort -gr

      The numbers to the left hand side indicate the number of times the acronym appears in the text. To remove the numbers, remove the -c flag of the uniq command (and hence you will not longer need the second sort command).

  2. Thanks for review, it was excellent and very informative.
    thank you :)