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Linux tr

The command ‘tr’ stands for ‘translate’. It is used to translate, like from lowercase to uppercase and vice versa or new lines into spaces.

Syntax:

Change Case

The ‘tr’ command can change case.

Syntax:

Example:

Look at the above snapshot, all p,r,c,u are converted into upprecase P,R,C,U.

Remove New Lines

To write all the lines into a single line we have to translate all new lines into spaces.

Syntax:

Example:

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tr Options

• tr -s : The ‘tr -s’ command squeezes the occurence of multiple characters into one.

Syntax:

command | tr -s <‘letter’>

Example:

cat jtp.txt | tr -s ‘l’ cat spaces.txt | tr -s ‘ ‘



Look at the above snapshot, command “cat jtp.txt | tr -s ‘l'” has squeezed all the letters ‘l’ into one and command “cat spaces.txt | tr -s ‘ ‘” has squeezed all the spaces into single space.

• tr rot13: This command encrypts the text. It is case-sensitive.

Example:

cat exm.txt | tr ‘a-z’ ‘nopqrstuvwxyzabcdefghijklm’ cat exm.txt | tr ‘a-z’ ‘n-za-m’



Look at the above snapshot, all the letters are encrypted according to the command. But letter ‘A’ and ‘M’ are not encrypted as they are in upper case.

• tr -d: The ‘tr -d’ command is used to delete characters.

Syntax:

command | tr -d

Example:

cat exm.txt | tr -d o



Look at the above snapshot, all the ‘o’ letters are deleted from the file ‘exm.txt’.