linux - Repeating regex replace with SED -

linux - Repeating regex replace with SED -

i have next lines (in reality there ~1m of these lines):

foo|||bar qux||boo|fzx

note every line contain 4 fields, number of characters can more 3.

what want replace every|| |nil| resulting:

foo|nil|nil|bar qux|nil|boo|fzx

what's way sed?

i tried fail:

sed 's/||/|nil/g'

you need repeat substitution until doesn't change:

sed ':a; s/||/|nil|/g; ta'

however not handle empty fields @ origin or end, need 2 more patterns:

sed 's/^|/nil|/; s/|$/|nil/; :a; s/||/|nil|/g; ta'

testing

input:

cat << eof > infile foo|||bar qux||boo|fzx ||| eof

run it:

<infile sed 's/^|/nil|/; s/|$/|nil/; :a; s/||/|nil|/g; ta'

output:

foo|nil|nil|bar qux|nil|boo|fzx nil|nil|nil|nil an awk way awk '{ for(i=1;i<=nf;i++) if(length($i)==0) $i="nil" } 1' fs='|' ofs='|'

regex linux sed