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  • How to add line number at the beginning of each line


    There are many ways to do this, I will try to show some

    Sample file '/tmp/file'
    Apple
    Apricot
    Avocado
    Banana
    Bilberry
    Blackberry
    Blackcurrant


    Method 1

    Using 'nl'
    # nl /tmp/file
         1  Apple
         2  Apricot
         3  Avocado
         4  Banana
         5  Bilberry
         6  Blackberry
         7  Blackcurrant

    Add a symbol after the numbers





    # nl -s ". " /tmp/file
         1. Apple
         2. Apricot
         3. Avocado
         4. Banana
         5. Bilberry
         6. Blackberry
         7. Blackcurrant

    Save the output to a file
    # nl -s ". " /tmp/file  > /tmp/newfile

    Method 2

    Using 'perl'
    #  perl -pe 'printf "%u. ", $.' /tmp/file
    1. Apple
    2. Apricot
    3. Avocado
    4. Banana
    5. Bilberry
    6. Blackberry
    7. Blackcurrant


    Method 3

    Using 'awk'
    # awk '{printf "%d. %s\n", NR, $0}' /tmp/file
    1. Apple
    2. Apricot
    3. Avocado
    4. Banana
    5. Bilberry
    6. Blackberry
    7. Blackcurrant




    # awk '{print NR".",$0}' /tmp/file
    1. Apple
    2. Apricot
    3. Avocado
    4. Banana
    5. Bilberry
    6. Blackberry
    7. Blackcurrant


    Method 4

    Using 'sed'
    # sed '=' /tmp/file | sed '{N;s/\n/. /}'
    1. Apple
    2. Apricot
    3. Avocado
    4. Banana
    5. Bilberry
    6. Blackberry
    7. Blackcurrant


    Deepak Prasad

    is a techie and an author who is still trying to survive in this IT generation with very little knowledge he has on Linux/Unix, VMware, SAN Storage, Automation, networking etc

    You can follow him on Facebook or Google+


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    How to add line number at the beginning of each line How to add line number at the beginning of each line Reviewed by Deepak Prasad on Saturday, June 24, 2017 Rating: 5

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