Introduction to Sed

Introduction to SED

Sed is String editor, Its used for editing lines in a file or a stream; Output re-directed to a new file or we can re-direct as a standard output.

Syntax: sed [options] 'command1' [files]

        sed [options] -e 'command1' [-e command2 ...] [files]

        sed [options] -f script [files]

Delete lines from 4 through 6 in file page.txt:

sed '4,6d' page.txt

Delete lines that contain "P" at the beginning of the line:

sed '/^P/d' page.txt

Translate capital R,T,O into small r,t,o:

sed 'y/CRO/cro/' page.txt

Delete empty lines:

sed '/^$/d' page.txt

Replace string C++ with Java for the first occurence on a line

sed 's/C++/Java/' page.txt

Remove pp string (replace with empty entry)for the first occurence on a line:

sed 's/pp//' page.txt

Remove ss string for all occurences on a line:

sed 's/pp//g' page.txt

Substitute a single space for any number of spaces wherever they occur on the

line:

sed 's/ */ /g' page.txt

Substitute underscore for any number of spaces wherever they occur on the

line:

sed 's/ */_/g' page.txt