#printSometimes it is desirable to specify thatthe characters to be changed are at the beginningof the line.  This uses the '^' character.  For example,  s/^ab/xy/pwill change "ab" to "xy" ONLY if "ab" begins the line.Remember that   s/ab/xy/pwould just change the first "ab" anywhere in the line.In this directory there is a file "text"; whenever theletters "cat" begin a line, change them to "mouse; but leaveother instances of "cat" unaltered.  Do this on each line (it onlytakes one command, as you know).  Then rewrite the file andtype "ready".#create Refmouse's pawalley catmouse has nine liveslet the cat out of the bag#create textcat's pawalley catcat has nine liveslet the cat out of the bag#user#cmp Ref text#log#next39.1a 10