grep -f is not giving any result - grep

I am trying to exclude lines from a file containing some words from another file. For example in lines.txt I have:
my dog
my cat
my fish
and in words.txt:
cat
Unfortunately, the command grep -vif words.txt lines.txt doesn't work, but the command grep -vi cat lines.txt would give me the correct result, so I guess there is a problem with the -f option. I have no idea what could be the problem with such a simple syntax, and there are no empty lines in words.txt or lines.txt, I've already checked.

Related

using grep command to get spectfic word [LINUX]

I have a test.txt file with links for example:
google.com?test=
google.com?hello=
and this code
xargs -0 -n1 -a FUZZvul.txt -d '\n' -P 20 -I % curl -ks1L '%/?=DarkLotus' | grep -a 'DarkLotus'
When I type a specific word, such as DarkLotus, in the terminal, it checks the links in the file and it brings me the word which is reflected in the links i provided in the test file
There is no problem here, the problem is that I have many links, and when the result appears in the terminal, I do not know which site reflected the DarkLotus word.
How can i do it?
Try -n option. It shows the line number of file with the matched line.
Best Regards,
Haridas.
I'm not sure what you are up to there, but can you invert it? grep by default prints matching lines. The problem here is you are piping the input from the stdout of the previous commands into grep, and that can lack context at grep. Since you have a file to work with:
$ grep 'DarkLotus' FUZZvul.txt
If your intention is to also follow the link then it might be easier to write a bash script:
#!/bin/bash
for line in `grep 'DarkLotus FUZZvul.txt`
do
link=# extract link from line
echo ${link}
curl -ks1L ${link}
done
Then you could make your script accept user input:
#/bin/bash
word="${0}"
for line in `grep ${word} FUZZvul.txt`
...
and then
$ my_link_getter "DarkLotus"
https://google?somearg=DarkLotus
...
And then you could make the txt file a parameter.
etc.

grep: Find all files containing the word `star`, but not the word `start`

I have a bunch of files: some contain the word star, some contain the word start, some contain both.
I'd like to grep for files that contain the word star, but not the word start.
How can this be accomplished using only grep?
grep has some options for inverting the matches at the line or file level. You want the latter option, with the -L switch. The following will print the names of all the files in a folder that don't contain the text start:
grep -LF start *
-F tells grep that start is a literal string and not a regex. It's optional here, but might speed things up a tiny bit.
You can use the resulting list to search for files that contain star:
grep -lF star $(grep -LF start *)
-l prints only the names of files containing a match, not any line-by-line or match-by-match details. If this is not exactly what you want, man grep is your friend.
This uses an additional shell construct to run the inverted match, but it technically doesn't call any additional programs that aren't grep.
Update
Since you mention wanting to look through all the files starting with a given root folder, change -LF to -LFr. Replace * with your root folder if you don't want to change working directories.
-r tells grep to recurse into directories, and search every file it finds along the way.
With GNU grep for -w:
$ cat file
foo star bar
oof start rab
$ grep -w star *
foo star bar
or if you just want the names of the files containing star:
$ grep -lw star *
file
and to just find files to look in:
$ find . -maxdepth 1 -type f -exec grep -w 'star' {} \;
foo star bar

Getting all the matches with 'grep -f' option

I would like to find all the matches of the text I have in one file ('file1.txt') that are found in another file ('file2.txt') using the grep option -f, that tells to read the expressions to be found from file.
'file1.txt'
a
a
'file2.txt'
a
When I run the command:
grep -f file1.txt file2.txt -w
I get only once the output of the 'a'. instead I would like to get it twice, because it occurs twice in my 'file1.txt' file. Is there a way to let grep (or any other unix/linux) tool to output a match for each line it reads?
Thanks in advance.
Arturo
Grep works as designed, giving only one output line.
You could use another approach:
while IFS= read -r pattern; do
grep -e $pattern file2.txt
done < file1.txt
This would use every line in file1.txt as a pattern for the grep, thus resulting in the output you're looking for.
When you use
grep -f pattern.txt file.txt
It means match the pattern found in pattern.txt in the file file.txt.
It is giving you only one output because that is all is there in the second file.
Try interchanging the files,
grep -f file2.txt file1.txt -w
Does this answer your question?

grep mistaking pattern for file?

cat file.txt | grep -x "\d*"
grep: \Documents and Settings: Is a directory
I want to search file.txt for any lines that are numbers only but grep seems to be viewing \d* as a wildcard for files and not the pattern. How can I specify that it's the pattern and it should use stdin for what to grep over?
The file is full of lines of datetime stamps, some end with a letter, some don't.
20140110122200
20131208041510M
...
I'm trying to only get the lines that don't end in a letter.
EDIT: I've also tried setting the filename instead of piping it with cat. Not much different.
C:\long\path>grep -ex "\d*" -f file.txt
grep: \Dell: Is a directory
grep: \Documents and Settings: Is a directory
Why are you using cat to pass the file to grep? Why not just give grep the filename directly?
grep -x '\d*' file.txt
I think the actual problem you're seeing is that the * wildcard is being expanded. That's why grep is giving you errors that mention actual directories (beginning with 'd') on your system.

grep using a list to find matches in a file, and print only the first occurrence for each string in the list

I have a file, for example, "queries.txt" that has hard return separated strings. I want to use this list to find matches in a second file, "biglist.txt".
"biglist.txt" may have multiple matches for each string in "queries.txt". I want to return only the first hit for each query and write this to another file.
grep -m 1 -wf queries.txt biglist.txt > output
only gives me one line in output. I should have output that is the same number of lines as queries.txt.
Any suggestions for this? Many thanks! I searched for past questions but did not find one that was exactly the same sort of case after a few minutes of reading.
If you want to "reset the counter" after each file, you could do
cat queries.txt | xargs -I{} grep -m 1 -w {} biglist.txt > output
This uses xargs to call grep once for each line in the input… should do the trick for you.
Explanation:
cat queries.txt - produce one "search word" per line
xargs -I{} - take the input one line at a time, and insert it at {}
grep -m 1 -w - find only one match of a whole word
{} - this is where xargs inserts the search term (once per call)
biglist.txt - the file to be searched
> output - the file where the result is to be written
An alternate method without xargs (which one should indeed learn):
(this method assumes there are no spaces in the lines in queries.txt)
cat queries.txt | while read target; do grep -m 1 $target biglist.txt; done > outr
I might not fully understand your question, but it sounds like something like this might work.
cat queries.txt | while read word; do grep "$word" biglist.txt | tee -a output.txt; done

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