使用 sed 删除多个主题标签

Question

I'm writing a bash script on OSX. There's a lot of grep and sed going on, all working fine, with one exception: I can't figure out how to remove multiple hashtags.

This removes ALL hashtags, no problem:

sed 's/#[^ ]*//g'

I expected this to remove specific hashtags:

sed "s/#(tag1|tag2)//g"

But it doesn't remove anything.

I thought the # symbol might be a special character so I tried without:

sed "s/(tag1|tag2)//g"

It makes no difference, neither tag1 nor tag2 are removed.

But if I try:

sed "s/tag1//g"

Then tag1 is removed, leaving the #.

If I then try:

sed "s/#tag1//g"

Nothing happens! It doesn't remove tag1 or #tag1.

Could anyone point out where I'm going wrong please?

EDIT: This is the code:

results=($( \
echo "$ContentsOfHTMLFile" \
| sed -E "s/#(tag1|tag2|tag3)//g" \
| grep -iEo "<p.*>.*$VariableContainingSearchTerms\D.*</p>" \
| grep -iEo "<p.*>.*$VariableContainingSearchTerms.*</p>" \
| grep -Ev $VariableContainingSearchTermsToExclude \
| sed 's/<[^>]*>//g' \
| sed 's/http[^ ]*//g' \
| sed 's/^[[:space:]]*//' \
| sed 's/[[:space:]]*$//' \
))

So what I'm trying to do is:

1. Remove certain hashtags.
2. Search for <p></p> blocks that contain certain terms.
3. Only keep the blocks that contain certain other terms.
4. Strip all <> blocks.
5. Strip all URLs.
6. Strip all leading whitespace.
7. Strip all trailing whitespace.

Everything from 2-7 works as it should. It's just the hashtags I'm having a problem with. I've also tried doing the hashtags at other points in the sequence, but it makes no difference.

Answer 1

Try:

sed -E 's/#(tag1|tag2)//g'

From sed's help:

  -E, -r, --regexp-extended
                 use extended regular expressions in the script
                 (for portability use POSIX -E).

Answer 2

POSIX standard sed does not support | in regex, you can use two s es instead, like this:

sed -e 's/#tag1//g;s/#tag2//g;'

Or

sed -e 's/#tag1//g;' -e 's/#tag2//g;'

Btw, it also needs to use \\( and \\) to group things.
( and ) will match the parens literally.