File persons.txt used for demonstration purposes (no., name, birth year, height, weight):
1. Piotr 1989 184 70.2
2. Tomasz 1994 172 60.8
3. Paweł 2003 104 48.4
4. Marcin 1980 174 91.6
5. Michał 1990 168 74.9
6. Lucjan 2000 80 44.1
7. Paweł 2000 124 60.2
8. Rafał 1980 174 91.6
9. Michał 1998 139 89.1
10. Damian 1994 170 68.2
Displays all rows from the persons.txt file. All rows containing word "Paweł" are displayed double:
sed '/Paweł/ p' persons.txt
Displays only rows containing word "Paweł":
sed -n '/Paweł/ p' persons.txt
Displays rows starting at second and ending at fourth:
sed -n '2,4 p' persons.txt
Displays all rows but second, third and fourth:
sed -n '2,4 !p' persons.txt
Displays first four rows (counterpart for: head -4 persons.txt):
sed '4 q' persons.txt
Appends a row 'New row' after the third row and displays new content:
sed '3 a New row' persons.txt
Prepends a row 'New row' before each row containing string '99' and displays new content:
sed '/99/ i New row' persons.txt
Replaces 7th and 8th rows with new content (file persons.txt stays unmodified):
sed '7,8 c New content' persons.txt
Replaces all rows containing string '99' with new two lines content:
sed '/99/ c Linijka #1\nLinijka #2' persons.txt
Replaces each 'n' character with 'N' one and displays new content:
sed 's/n/N/g' persons.txt
Replaces each 'n' character with 'N' one and displays only modified rows:
sed -n 's/n/N/g p' persons.txt
Removes first row:
sed '1 d' persons.txt
Adds four spaces at the beginning of each not empty line. Character '&' is replaced with matched string:
sed 's/^./ &/' persons.txt
or (works for every line):
sed 's/^/ /' persons.txt
Removes spaces from the ending of each line:
sed 's/ *$//'
Removes all \r characters (carriage return) and saves modified content to the file persons.txt:
sed -i 's/\r//g' persons.txt
Removes all spaces from the beginning of each line and saves modified content to the file persons.txt:
sed -i 's/^ *//' persons.txt
Prepends with a space character each line that starts with any character followed by a dot ('.')
and saves modified content to the file persons.txt
sed -i 's/^.\./ &/' persons.txt