tr:tldr:3b86a

This command is used to replace a specific character in a string or text with another character. Let's break down the command:

• echo ${text}: This part outputs the value of the variable ${text}. The variable ${text} should be assigned a string or a text that you want to modify.
• |: This is called the pipe operator and it is used to redirect the output of the preceding command to the input of the succeeding command.
• tr ${find_character} ${replace_character}: This part uses the tr command to perform the character replacement. The variable ${find_character} should contain the character you want to find, and the variable ${replace_character} should contain the character you want to replace it with.

To give an example, let's say we have the following command:

echo "Hello, world!" | tr o e

This command will replace all occurrences of the letter 'o' with the letter 'e' in the string "Hello, world!". So, the output of this command would be:

Hello, werld!

Note that the tr command only replaces single characters, not multiple characters or substrings.