sh-2.02$ cat file
This is a test file with some lines in it with a word or two and some he words.
He went to the market with he, she and it.
he he he and they are word sentences.
This line ends with word
There are more lines with he in it he as is .

sh-2.02$ sed s/he/she/ file
This is a test file with some lines in it with a word or two and some she words.
He went to tshe market with he, she and it.
she he he and they are word sentences.
This line ends with word
Tshere are more lines with he in it he as is .

sh-2.02$ sed s/he/she/g file
This is a test file with some lines in it with a word or two and some she words.
He went to tshe market with she, sshe and it.
she she she and tshey are word sentences.
This line ends with word
Tshere are more lines with she in it she as is .

sh-2.02$ sed 1s/he/she/g file
This is a test file with some lines in it with a word or two and some she words.
He went to the market with he, she and it.
he he he and they are word sentences.
This line ends with word
There are more lines with he in it he as is .

sh-2.02$ sed s/word.*/word/ file
This is a test file with some lines in it with a word
He went to the market with he, she and it.
he he he and they are word
This line ends with word
There are more lines with he in it he as is .

sh-2.02$ sed s/word.*/word./ file
This is a test file with some lines in it with a word.
He went to the market with he, she and it.
he he he and they are word.
This line ends with word.
There are more lines with he in it he as is .

sh-2.02$ sed 2d file
This is a test file with some lines in it with a word or two and some he words.
he he he and they are word sentences.
This line ends with word
There are more lines with he in it he as is .

sh-2.02$ sed 1,2d file
he he he and they are word sentences.
This line ends with word
There are more lines with he in it he as is .

sh-2.02$ sed /more/d file
This is a test file with some lines in it with a word or two and some he words.
He went to the market with he, she and it.
he he he and they are word sentences.
This line ends with word

sh-2.02$ sed /more/p file
This is a test file with some lines in it with a word or two and some he words.
He went to the market with he, she and it.
he he he and they are word sentences.
This line ends with word
There are more lines with he in it he as is .
There are more lines with he in it he as is .

sh-2.02$ sed -n /more/p file
There are more lines with he in it he as is .

sh-2.02$ cat file
This is a test file with some lines in it with a word or two and some he words.
He went to the market with he, she and it.
he he he and they are word sentences.
This line ends with word
There are more lines with he in it he as is .

this is another test line.
sh-2.02$ sed /test/s/is/at/ file
That is a test file with some lines in it with a word or two and some he words.
He went to the market with he, she and it.
he he he and they are word sentences.
This line ends with word
There are more lines with he in it he as is .

that is another test line.
sh-2.02$ sed s/i/x/2 file
This xs a test file with some lines in it with a word or two and some he words.
He went to the market with he, she and xt.
he he he and they are word sentences.
This lxne ends with word
There are more lines wxth he in it he as is .

this xs another test line.
sh-2.02$ sed = file
1
This is a test file with some lines in it with a word or two and some he words.
2
He went to the market with he, she and it.
3
he he he and they are word sentences.
4
This line ends with word
5
There are more lines with he in it he as is .
6

7
this is another test line.