Awesome ! Let's call it sed !
Reference: https://www.gnu.org/software/sed/manual/sed.html#Examples
Sorry, I couldn't miss that one. :) Really, check the example. Sed is most powerful tool and can do astonishing work.
Reference: https://www.gnu.org/software/sed/manual/sed.html#Examples
Sorry, I couldn't miss that one. :) Really, check the example. Sed is most powerful tool and can do astonishing work.
It would however be nice to have a tool with similar power but simpler, more comprehensible syntax. One of the other commenters linked to an interesting document on sam, which has a better control flow but equally arcane syntax.
Streams are a non-trivial construction, after all.
>leaves a blank line at the beginning and end if there are some already.
#!/usr/bin/sed -f
# on empty lines, join with next
# Note there is a star in the regexp
:x
/^\n*$/ {
N
bx
}
# now, squeeze all '\n', this can be also done by:
# s/^\(\n\)*/\1/
s/\n*/\
/
Arcane. Some would call it archaic too :)
> Streams are a non-trivial construction, after all.
...
> Well, sorry but sed _is_ cryptic. Let me quote an exemple for you (squeezing blank lines):
I agree with you that sed is cryptic, but I don't think that that necessarily means that stream processing languages are doomed to have an archaic syntax. I'd also agree with marvy in saying that the car and house example is very clear as to it's intent:
STDIN | /\w+/{|word|
/house/ {
# when word is house
}
/car/ {
# when word is car
}
{
# default case
}
}
EDITS: formatting.
With Perl 5, Perl essentially repositioned itself as a full-blown, general-purpose programming language, with all the power that entailed, but still stuck with a syntax based on essentially trying to be a more powerful and consistent superset of sed and awk.
These days, I think we could do a lot better with a stream processor with the stream-processing focus and one-liner power of Perl 4 but without the needless (these days) constraint of retaining the syntactic hash of ancient unix utilities.
I'd argue that makes it one of the least useful documents you've ever read :)
A job for life! :-)