How do I use grep to search for "-f". it seems to interpret this as an option in the grep command rather than an actual string.
arecord --help | grep "-f"
I want to be able to search through the argument options for the arecord command
Related
I am trying to search for files with specific text but excluding a certain text and showing only the files.
Here is my code:
grep -v "TEXT1" *.* | grep -ils "ABC2"
However, it returns:
(standard input)
Please suggest. Thanks a lot.
The output should only show the filenames.
Here's one way to do it, assuming you want to match these terms anywhere in the file.
grep -LZ 'TEXT1' *.* | xargs -0 grep -li 'ABC2'
-L will match files not containing the given search term
use -LiZ if you want to match TEXT1 irrespective of case
The -Z option is needed to separate filenames with NUL character and xargs -0 will then separate out filenames based on NUL character
If you want to check these two conditions on same line instead of anywhere in the file:
grep -lP '^(?!.*TEXT1).*(?i:ABC2)' *.*
-P enables PCRE, which I assume you have since linux is tagged
(?!regexp) is a negative lookahead construct, so ^(?!.*TEXT1) will ensure the line doesn't have TEXT1
(?i:ABC2) will match ABC2 case insensitively
Use grep -liP '^(?!.*TEXT1).*ABC2' if you want to match both terms irrespective of case
(standard input)
This error is due to use of grep -l in a pipeline as your second grep command is reading input from stdin not from a file and -l option is printing (standard input) instead of the filename.
You can use this alternate solution in a single awk command:
awk '/ABC2/ && !/TEXT1/ {print FILENAME; nextfile}' *.* 2>/dev/null
I wanted to grep the word "force" but most of the output listed is from the command -force.
When I did grep -v "-force" filename , it says grep : orce most probably because of the -f command.
I just want to find a force signal from files using grep. How?
use grep -v -- "-force" - the double - signals that there are no more options being expected.
If you want to grep specific word from file then we can use cat command
# cat filename.txt | grep force
For other basic Commands
this line maybe simpler:
grep '[^-]force' tmp
it says: grep "force", but only if it does not has a prefix - by using [^]. See some simple regular expression examples here.
Use [-] to remove the special significance. Check this out:
> cat rand_file.txt
1. list items of random text
2. -force
3. look similar as the first batch
4. force
5. some random text
> grep -v "-force" rand_file.txt
grep: orce: No such file or directory
> grep -v "[-]force" rand_file.txt | grep force
4. force
>
I have a basic log file that I'm trying to parse using grep.
My command is as follows:
grep 'Rate for the playback =\|Dumping\|ERROR\|*** Starting' ENCL_overnight_loop20160118_173202.log | egrep -v -A40 'DumpDataComp'
I've also tried
grep -e 'Rate for the playback =\|Dumping\|ERROR\|*** Starting' -e -A40 'DumpDataComp' ENCL_overnight_loop20160118_173202.log
Neither of these commands seem to account for the -A40 argument. The grep works in finding the condition, but the 40 lines that trail do not print.
What am I doing wrong?
In grep, when I try to find a pattern in the man page, the pattern is treated as the option of grep if it starts with -. For example, I find someone is using uname -r and I wonder what does -r means for uname.
uname --help | grep '-r'
But I got the following error,
Usage: grep [OPTION]... PATTERN [FILE]...
Try `grep --help' for more information.
Seems as if -r is treated as an option for grep.
There are two ways:
If supported by your version, use -- to stop argument processing.
uname --help | grep -- '-r'
Use the -e option to specify the pattern. Since it expects an argument,
grep will not treat the next string as a new option just because it starts with a hyphen.
uname --help | grep -e '-r'
As described in the man page for grep:
-e PATTERN, --regexp=PATTERN
Use PATTERN as the pattern. This can be used to specify multiple search patterns, or to protect a pattern beginning with a hyphen (-). (-e is specified by POSIX.)
uname --help | grep -e -r does what is expected.
Backslash also seems to help:
uname --help | grep "\-r"
uname --help | grep '\-r'
How do I pipe the output of grep as the search pattern for another grep?
As an example:
grep <Search_term> <file1> | xargs grep <file2>
I want the output of the first grep as the search term for the second grep. The above command is treating the output of the first grep as the file name for the second grep. I tried using the -e option for the second grep, but it does not work either.
You need to use xargs's -i switch:
grep ... | xargs -ifoo grep foo file_in_which_to_search
This takes the option after -i (foo in this case) and replaces every occurrence of it in the command with the output of the first grep.
This is the same as:
grep `grep ...` file_in_which_to_search
Try
grep ... | fgrep -f - file1 file2 ...
If using Bash then you can use backticks:
> grep -e "`grep ... ...`" files
the -e flag and the double quotes are there to ensure that any output from the initial grep that starts with a hyphen isn't then interpreted as an option to the second grep.
Note that the double quoting trick (which also ensures that the output from grep is treated as a single parameter) only works with Bash. It doesn't appear to work with (t)csh.
Note also that backticks are the standard way to get the output from one program into the parameter list of another. Not all programs have a convenient way to read parameters from stdin the way that (f)grep does.
I wanted to search for text in files (using grep) that had a certain pattern in their file names (found using find) in the current directory. I used the following command:
grep -i "pattern1" $(find . -name "pattern2")
Here pattern2 is the pattern in the file names and pattern1 is the pattern searched for
within files matching pattern2.
edit: Not strictly piping but still related and quite useful...
This is what I use to search for a file from a listing:
ls -la | grep 'file-in-which-to-search'
Okay breaking the rules as this isn't an answer, just a note that I can't get any of these solutions to work.
% fgrep -f test file
works fine.
% cat test | fgrep -f - file
fgrep: -: No such file or directory
fails.
% cat test | xargs -ifoo grep foo file
xargs: illegal option -- i
usage: xargs [-0opt] [-E eofstr] [-I replstr [-R replacements]] [-J replstr]
[-L number] [-n number [-x]] [-P maxprocs] [-s size]
[utility [argument ...]]
fails. Note that a capital I is necessary. If i use that all is good.
% grep "`cat test`" file
kinda works in that it returns a line for the terms that match but it also returns a line grep: line 3 in test: No such file or directory for each file that doesn't find a match.
Am I missing something or is this just differences in my Darwin distribution or bash shell?
I tried this way , and it works great.
[opuser#vjmachine abc]$ cat a
not problem
all
problem
first
not to get
read problem
read not problem
[opuser#vjmachine abc]$ cat b
not problem xxy
problem abcd
read problem werwer
read not problem 98989
123 not problem 345
345 problem tyu
[opuser#vjmachine abc]$ grep -e "`grep problem a`" b --col
not problem xxy
problem abcd
read problem werwer
read not problem 98989
123 not problem 345
345 problem tyu
[opuser#vjmachine abc]$
You should grep in such a way, to extract filenames only, see the parameter -l (the lowercase L):
grep -l someSearch * | xargs grep otherSearch
Because on the simple grep, the output is much more info than file names only. For instance when you do
grep someSearch *
You will pipe to xargs info like this
filename1: blablabla someSearch blablabla something else
filename2: bla someSearch bla otherSearch
...
Piping any of above line makes nonsense to pass to xargs.
But when you do grep -l someSearch *, your output will look like this:
filename1
filename2
Such an output can be passed now to xargs
I have found the following command to work using $() with my first command inside the parenthesis to have the shell execute it first.
grep $(dig +short) file
I use this to look through files for an IP address when I am given a host name.