CODEWITHSUNDEEP
bashawksedgrep
g0tr00t
g0tr00t

Reputation: 69

Print all characters upto a matching pattern from a file

Maybe a silly question but I have a text file that needs to display everything upto the first pattern match which is a '/'. (all lines contain no blank spaces)

Example.txt:

somename/for/example/
something/as/another/example
thisfile/dir/dir/example

Preferred output:

somename
something
thisfile

I know this grep code will display everything after a matching pattern:

grep -o '/[^\n]*' '/my/file.txt'

So is there any way to do the complete opposite, maybe rm everything after matching pattern or invert to display my preferred output?

Thanks.

Upvotes: 2

Views: 116

Answers (4)

Avinash Raj
Avinash Raj

Reputation: 174796

You just need to include starting anchor ^ and also the / in a negated character class.

grep -o '^[^/]*' file

Upvotes: 0

Arjun Mathew Dan
Arjun Mathew Dan

Reputation: 5298

Assuming filename as "file.txt"

cat file.txt | cut -d "/" -f 1

Here, we are cutting the input line with "/" as the delimiter (-d "/"). Then we select the first field (-f 1).

Upvotes: 0

symlink
symlink

Reputation: 12218

Yu can use a much simpler reg exp:

/[^/]*/

The forward slash after the carat is what you're matching to.

jsFiddle

Upvotes: 0

shellter
shellter

Reputation: 37298

If you're calling an external command like grep, you can get the same results your require with the sed command, i.e.

 echo "something/as/another/example" | sed 's:/.*::'
 something

Instead of focusing on what you want to keep, think about what you want to remove, in this case everything after the first '/' char. This is what this sed command does.

The leading s means substitute, the :/.*: is the pattern to match, with /.* meaning match the first /' char and all characters after that. The 2nd half of thesedcommand is the replacement. With::`, this means replace with nothing.

The traditional idom for sed is to use s/str/rep/, using / chars to delimit the search from the replacement, but you can use any character you want after the initial s (substitute) command.

Some seds expect the / char, and want a special indication that the following character is the sub/replace delimiter. So if s:/.*:: doesn't work, then s\:/.*:: should work.

IHTH.

Upvotes: 1

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