[SOLVED] stupid question about splitting command on more lines and comment them...

masavini · 10-21-2013, 06:24 AM

hi,
when i split a sed command on more lines, i'm not able to add comment to each line:

Code:

echo "bubu" | \
	# new line after a pipe is not a problem
	sed -e 's/b/c/' \
		# new line with no pipe does not work...
		-e 's/b/c/'

can someone tell me if it's possible to add comment lines between a "non piped" splitted command?

i know that the backslashes escape the return char, so the multiline command will be read as a one-liner... so it should not be possible...

if it's a stupid question (and i'm really afraid so), just sorry...

kabamaru · 10-21-2013, 06:59 AM

Code:

echo "bubu" |
  sed '# comment
       s/b/c/
       # comment
       s/u/a/'

55020 · 10-21-2013, 07:01 AM

You can abuse the "back tick" command substitution, but this solution is probably more ugly and confusing than the original problem:

Code:

sed -e 's/1/a/' \
    -e 's/2/b/' `# this comment is hiding inside a command substitution` \
    -e 's/3/c/'

masavini · 10-21-2013, 07:24 AM

this is not that bad:

Code:

echo "bubu" | \
	sed -e 's/b/a/' \
		`# this comment is hiding inside a command substitution` \
	    -e 's/a/b/' \
	    -e 's/u/c/'

thanks!

masavini · 10-21-2013, 07:26 AM

Quote:

Originally Posted by kabamaru

Code:

echo "bubu" |
  sed '# comment
       s/b/c/
       # comment
       s/u/a/'

this is nice, but it becomes tricky if sed commands contain more '...

kabamaru · 10-21-2013, 07:56 AM

Quote:

Originally Posted by masavini

this is nice, but it becomes tricky if sed commands contain more '...

What you say also applies to sed -e '...'. If you have single quotes inside the sed command you can:

a) use double-quotes to enclose the sed command:

Code:

echo "'" | sed -e "s/'/single-quote/"

b) if your sed commands are complex (multiple commands, special characters etc.), it's more elegant to just put all these to a sed script, where you don't worry about quotes, comments etc. and just call your script with:

Code:

echo "bubu" | sed -f sedscr