sed.txt

#Sed is stream editor, editing text on the fly. Can redirect text in or use a file

#Substitue/replace first occurance of a string in a line
sed 's/<old string>/<new string>/'

#To have multiple commands use -e, can also use {}
sed -e 's/<old string>/<new string>/'; 's/<old string>/<new string>/'

#To substitue the 2nd occurance of string in every line
sed 's/<old string>/<new string>/2'

#To substitue the every occurance of string in every line
sed 's/<old string>/<new string>/g'

#Save sed output to a file
sed 's/<old string>/<new string>/w <filename>'

#To substitue the string only on line 2
sed '2s/<old string>/<new string>/'

#To substitue the string only on lines 2 and 3
sed '2,3s/<old string>/<new string>/'

#To substitue the string starting on line 2 to end of document
sed '2,$s/<old string>/<new string>/'

#To substitue a string only on line where something is in text
sed '/<something>/s/<old string>/<new string>/'

#To delete line number 4 from output
sed '4d'

#To delete lines 3 and 4
sed '3,4d'

#To insert new line of text at the begining of each line, insert uses \ 
sed 'i\<string>\'

#To append new line of text to end of each line
sed 'a\<string>'

#Change an entire 4th line for the new string
sed '4c\<new line>'

#Replace character sets, a with x, b with y, c with z
sed 'y/abc/xyz'

#Add line numbers to output 
sed '='