one-liner 'in-place' file edits

several ways to skin ze cat, and get a tasty snack:

$ cat alchemy

turn lead to gold

python:

$ python -c "import sys,fileinput,re;[sys.stdout.write(re.sub('lead','sardines',line)) for line in fileinput.input('alchemy',inplace=1)]"

$ cat alchemy

turn sardines to gold

perl:

$ perl -p -i -e"s#gold#cracker topping#" alchemy

$ cat alchemy

turn sardines to cracker topping

gnu sed:

$ sed -i -e "s/sardines/cream\ cheese/" alchemy

$ cat alchemy

turn cream cheese to cracker topping

good ol' ed:

$ printf '%s\n' ',s/cracker\ topping/cheesecake/' w q | ed -s alchemy

$ cat alchemy

turn cream cheese to cheesecake

So, the next time you are asked to turn lead to cheesecake, it will be no real problem.