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In this lecture we will see substitute command in action.

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But firstly what's the content of our test file table.

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Text we can for example the place name Jorm with name Richard.

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So what I said use one letter command as followed by Sri slushes and inside first two slices of right.

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And into replacement part right.

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Richard the input file will be table dot text

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and we see that in output we don't see John anywhere.

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He was replaced by Richard grade when we put in the content of profile we still see John here as set

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by default doesn't change input file.

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Now let's say we want to replace John with Richard but only on second line.

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So in other place before as commom

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Vitthal both Number two

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if Iranian

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We don't see any change as patterns on what was not found on second line.

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The same will be for faultline.

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But if you specify to do the change on line

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we see that John was replaced by Richard great.

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Now we can again display content of our testing file and let's say that we want to do a replacement

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for our president which will be from first to last line.

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So we are using as an address one comma

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dollar sign which means from first to last line and we will replace John with name Richard

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and it is working great again again print output of our file to see clearly.

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Is there if you can do some experiment.

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So firstly copy it they both file

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too tables sorry not.

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And now we can do replacement directly in input file.

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So we are using option I know out what should be printed to standard output here.

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So with that option we did option I would replace men John to Richard

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as an input file will be table so got text so no output is printed here.

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Which is correct.

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And if we show output of tables read the text we see that Richard is here instead of which on great.

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Now we can do some other examples on initial table file.

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So it's output using cut command

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and now imagine that your boss thought due to height age of partisans whose age is a greater density

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and you can hide it by three steps.

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So in our substitute command we need to say X which are very much set they are more so that need to

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be two numbers and first Vama will be in a strange city to 9.

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Second number can be represented by digital Clouse which represents any number from 0 to 9.

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Be aware that in this example I am assuming that no one will be older than 99.

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Otherwise we would need to adjust I guess a little bit and I guess we can replace if it's three steps.

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So even around the gray we see he didn't age four Peter who had 50.

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And for Mark who has said this theory this works perfectly.

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Now show again output of our testing file.

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And let's say that we want to replace.

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But then H.

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R. with three times printed h.

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So instead for printing three times h r we can use Surete times ampersand symbol

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and days unperson symbol represents.

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Just think that Menchie's directx and even the we see that in our food is three times splinted age are

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great.

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This ampersand symbol is a very helpful when you want to print something which matches require expressions

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while you don't know how that string looks like.