Writing a small bootstrap 3 downgrader in sed
Some notes on sed:
always use -E for the more ‘standard’ regex
always use single quotes for the regex so that you don’t have to escape metacharacters
sed doesnt allow for non capture groups
you can execute a script with -e (not nessecary for a regex)
chop up your regexs into smaller ones and use -e to seperate out regexs by ;s
you can use -i to change a file on the fly. use .bak for a backup as you write or . for none
example:
sed -E \
-e 's/(col-sm-)|(col-md-)([0-9]+)/span\3/g;s/span([0-9]+) span[0-9]+/span\1/g' \
-i.bak <template>.html
Running this agains multiple files requires you to find all files:
find *.html -type f -print0
-print0 always evaluates to true and prints to stout followed by an ASCII NUL character (\0).
then pipe each result into xargs - -0 takes \0 as a seperator, -n is the number of arguments the utility takes:
xargs -0 -n 1 < <utility> <utility args> >
Putting this all together:
find *.html -type f -print0 | \
xargs -0 -n 1 \
sed -E -i.bak \
-e 's/(col-sm-)|(col-md-)([0-9]+)/span\3/g;s/span([0-9]+) span[0-9]+/span\1/g'
And we’ve created our bootstrap 3 downgrader!