grep seems to ignore --include

Question

man grep says

grep [OPTIONS] PATTERN [FILE...]

. . .

   --include=GLOB
          Search  only  files whose base name matches GLOB (using wildcard
          matching as described under --exclude).

So I typed

grep --include="*.html" 'li' *

to search for instances of li in HTML files in the current directory. Instead I get a list of every use of li anywhere in the directory, even in the non-HTML files. What am I doing wrong? I tried all kinds of variants like

grep --include=\*.html 'li' *

but without any luck.

Answer 1

--include=PATTERN only works when you add -r

$ grep -r --include='*.html' 'li' .

-R, -r, --recursive   Read all files under each directory, recursively; this is equivalent to the -d recurse option.
--include=PATTERN     Recurse in directories only searching file matching PATTERN.
--exclude=PATTERN     Recurse in directories skip file matching PATTERN.

Answer 2

The shell you're using (bash, tsh, zsh, etc) will dictate the commandline globbing that will and won't work. Most people use bash because it's installed by default on many distros - I use bash.

The following syntax has always worked for me.

    grep -r --include=*.html li *

1. As mentioned above, the -r switch allows grep to search subdirectories, otherwise it won't, which makes it look like the grep failed.
2. Simple file type inclusions (one extension) need no tweeking.
3. Don't quote (single or double) the inclusion, the parser doesn't like it

For inclusions of multiple extensions I use a bash brace expansion.

    grep -r --include=*.{html,htm,js} li *

Other things to try if you are still having trouble

1. Escape the * to protect it when it's parsed by the shell

   grep -r --include=\*.html li *
   

2. Make the search path more explicit

   grep -r --include=\*.html li ./*
   

Hope that helps

Answer 3

find $directoryname -maxdepth 1 -name '*.html' | xargs grep 'li' Here -maxdepth 1 is for searching only in the directory and not its subdirectories. If you want to search even in sub directory remove -maxdepth 1 in the command.

Answer 4

grep -version doesn't work, but grep --version gives

grep (GNU grep) 2.9

and the copyright statement.

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grep 'li' *.html

gets the shell to do the globbing, which isn't useful to me since I want to recurse.

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I originally tried the command with -R (or -r) but that didn't work either. The command recurses but brings up files without html in the name (or anywhere in the path). So that's not it either.

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I'd post these as comments or edit into the original but for some reason StackExchange isn't properly associating my account. (Mods: please comment-ify this!)