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tr:tldr:79b5d
The command tr
stands for "translate," and it is a command-line utility in Unix-based operating systems used for character translation or deletion. The <
symbol is a type of input redirection that tells the command to take input from a specified file rather than the standard input.
The command you provided uses the tr
command to replace all occurrences of a character or set of characters specified by the variable ${find_character}
with another character or set of characters specified by the variable ${replace_character}
. It takes input from the file named ${filename}
.
To understand it better, let's break it down:
${find_character}
: This is a variable representing the character or set of characters you want to find and replace. For example, if${find_character}
is set toa
, it will find every occurrence of the letter "a" in the input.${replace_character}
: This is a variable representing the character or set of characters you want to replace the found character(s) with. For example, if${replace_character}
is set tob
, it will replace every occurrence of the character "a" with "b" in the input.< ${filename}
: This indicates that the input for thetr
command should come from the file named${filename}
rather than the standard input (keyboard).
Overall, this command translates or replaces characters in the input stream (either through keyboard input or a file) based on the values specified in ${find_character}
and ${replace_character}
.