escape

what is escape character

invoke an alternative interpretation on the following characters;

1. represent a special meaning which cannot be directly represented by alphabet; \n;

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\t: tab;
\n: move the cursor down to the newx line without return to the beegining(in unix, \n move to the beginning of the line) 
\r: carriage return(move the cursor to the beginning of the line without advacing to the next line) 

window: \r\n unix: \n

2. represent a speical meangin which have an undesired interpretation; ' " \