Shell script to translate uppercase text to lowercase

2 Comments

While shell scripting on UNIX/LINUX/SOLARIS/AIX et cetera, it is often a requirement to translate uppercase characters to lowercase characters.

It can be a user input or contents of a file that one might be processing using shell scripting.

Below one-liner uses ‘tr’ CLI to translate uppercase characters to lowercase characters.

# strName=”TECHSUTRAM IN LOWERCASE"
# echo $strName| tr ‘[A-Z]’ ‘[a-z]’
techsutram in lowercase

Simple, isn’t it? However, there is a catch. The ‘tr’ CLI used for translation might not work on all UNIX flavors to convert all uppercase characters to lowercase.

The trick is to use a slightly longer form of ‘tr’ to make translation almost portable to other UNIX flavors. So above code can be rewritten as,

# strName=”TECHSUTRAM IN LOWERCASE"
# echo $strName| tr ‘ABCDEFGHIJKLMNOPQRSTUVWXYZ’ ‘abcdefghijklmnopqrstuvwxyz’
techsutram in lowercase

The same mechanism works for translating lowercase characters to uppercase characters as below.

# strName=”techsutram in uppercase"
# echo $strName| tr  ‘abcdefghijklmnopqrstuvwxyz’ ‘ABCDEFGHIJKLMNOPQRSTUVWXYZ’
TECHSUTRAM IN UPPERCASE 

That’s it. This trick has worked for me.
Do you know any other common method that can be used to translate uppercase characters to lowercase characters? If YES then let everyone know in the comments below.

 

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2 comments:

  1. UnknownJuly 11, 2012 at 2:37 PM

    What if i want to convert the string " MyNamE" where each letter gets converted to the opposite case instead of the string as a whole ??

    The converted output for the above given string should be " mYnAMe ".

    ReplyDelete
  2. AnonymousOctober 15, 2012 at 5:39 PM

    Thanks for the tip. How to convert string to initcap (first letter of the word should be in uppercase and rest of the letter should be in lower case).
    tr command example in unix

    ReplyDelete

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