Eg- lets suppose I want to grep string VR030315ITVENDMXN. Then grep should not show VR030315ITVENDMXN-LPP or any additional things with VR030315ITVENDMXN .
Can you use anchors?
For instance:
grep '^VR030315ITVENDMXN$' file
There is a similar question here How to make grep only match if the entire line matches?
You need to use the -o (or --only-matching ) option in your command line option
Of you do not desire to have the filename displayed use the -h (--no-filename) option in addition to remove them.
Related
I am stuck on a homework question. The question asks to display the lines, with grep and I can't use -w option, that contain no duplicate vowels.
My teacher said to find the grep command that could display two or more 'a's in a line which would, I think, be grep 'a.*a' file and then find the grep command that would display two or more 'u's which, I think, would be grep 'u.*u' file, combine them and then I should be able to get it. But I don't know how I would combine the grep commands.
You can combine different regular expressions with |:
grep 'a.*a|e.*e|i.*i|o.*o|u.*u' file
I am trying to use the following command to extract a substring from a string :
propertyPath=$(echo $path|awk '{print substr($0,3,$index)}')
However the command does not pick up the value of the $index variable and therefore does not return a valid substring.
This would work:
propertyPath=$(echo $path|awk '{print substr($0,3,'$index')}')
or
propertyPath=$(echo $path|awk -v index=$index '{print substr($0,3,index)}')
propertyPath=$(echo $path|awk "{print substr(\$0,1,$index)}")
Single quotes tell the shell not to expand values, so you'll have to use double quotes around your awk command. When you do that though, you'll have to escape the $ for the variables you do not want to expand early.
I have a file and i want to sort it according to a word and to remove the special characters.
The grep command is used to search for the characters
-b Display the block number at the beginning of each line.
-c Display the number of matched lines.
-h Display the matched lines, but do not display the filenames.
-i Ignore case sensitivity.
-l Display the filenames, but do not display the matched lines.
-n Display the matched lines and their line numbers.
-s Silent mode.
-v Display all lines that do NOT match.
-w Match whole word
but
How to use the grep command to do the file sort and remove the special character and number.
grep searches inside all the files to find matching text. It doesn't really sort and it doesn't really chop and change output. What you want is probably to use the sort command
sort <filename>
and the output sent to either the awk command or the sed command, which are common tools for manipulating text.
sort <filename> | sed 's/REPLACE/NEW_TEXT/g'
something like above I'd imagine.
The following command would do it.
sort FILE | tr -d 'LIST OF SPECIAL CHARS' > NEW_FILE
I want to grep for the string that starts with a dash/hyphen, like -X, in a file, but it's confusing this as a command line argument.
I've tried:
grep "-X"
grep \-X
grep '-X'
Use:
grep -- -X
Documentation
Related: What does a bare double dash mean? (thanks to nutty about natty).
The dash is a special character in Bash as noted at http://tldp.org/LDP/abs/html/special-chars.html#DASHREF. So escaping this once just gets you past Bash, but Grep still has it's own meaning to dashes (by providing options).
So you really need to escape it twice (if you prefer not to use the other mentioned answers). The following will/should work
grep \\-X
grep '\-X'
grep "\-X"
One way to try out how Bash passes arguments to a script/program is to create a .sh script that just echos all the arguments. I use a script called echo-args.sh to play with from time to time, all it contains is:
echo $*
I invoke it as:
bash echo-args.sh \-X
bash echo-args.sh \\-X
bash echo-args.sh "\-X"
You get the idea.
grep -e -X will do the trick.
grep -- -X
grep \\-X
grep '\-X'
grep "\-X"
grep -e -X
grep [-]X
I dont have access to a Solaris machine, but grep "\-X" works for me on linux.
The correct way would be to use "--" to stop processing arguments, as already mentioned. This is due to the usage of getopt_long (GNU C-function from getopt.h) in the source of the tool.
This is why you notice the same phenomena on other command-line tools; since most of them are GNU tools, and use this call,they exhibit the same behavior.
As a side note - getopt_long is what gives us the cool choice between -rlo and --really_long_option and the combination of arguments in the interpreter.
If you're using another utility that passes a single argument to grep, you can use:
'[-]X'
you can use nawk
$ nawk '/-X/{print}' file
None of the answers not helped me (ubuntu 20.04 LTS).
I found a bit another option:
My case:
systemctl --help | grep -w -- --user
-w will match a whole word.
-- means end of command arguments (to mark -w as not part of the grep command)
ls -l | grep "^-"
Hope this one would serve your purpose.
grep "^-X" file
It will grep and pick all the lines form the file.
^ in the grep"^" indicates a line starting with
I have a log file which contains a number of error lines, such as:
Failed to add email#test.com to database
I can filter these lines with a single grep call:
grep -E 'Failed to add (.*) to database'
This works fine, but what I'd really like to do is have grep (or another Unix command I pass the output into) only output the email address part of the matched line.
Is this possible?
sed is fine without grep:
sed -n 's/Failed to add \(.*\) to database/\1/p' filename
You can also just pipe grep to itself :)
grep -E 'Failed to add (.*) to database' | grep -Eo "[^ ]+#[^ ]+"
Or, if "lines in interest" are the only ones with emails, just use the last grep command without the first one.
You can use sed:
grep -E 'Failed to add (.*) to database'| sed 's/'Failed to add \(.*\) to database'/\1'
Recent versions of GNU grep have a -o option which does exactly what you want. (-o is for --only-matching).
This should do the job:
grep -x -e '(?<=Failed to add ).+?(?= to database)'
It uses a positive look-ahead assertion, followed by the match for the email address, followed by a postivie look-behind assertion. This insures that it matches the entire line, but only actually consumes (and thus returns) the email address part.
The -x option specifies that grep should match lines rather than the whole text.
or python:
cat file | python -c "import re, sys; print '\r\n'.join(re.findall('add (.*?) to', sys.stdin.read()))"
-r option for sed allows regexps without backslashes
sed -n -r 's/Failed to add (.*) to database/\1/p' filename
If you just want to use grep and output only matching part of line
grep -E -o 'Failed to add (.*) to database'
Then maybe if you want to write it to a file
cat yourlogfile | grep -E -o 'Failed to add (.*) to database' >> outputfile
So as of grep utility -o is going to -o, --only-matching show only nonempty parts of lines that match'.
If you want to use grep, it would be more appropiate to use egrep;
About egrep
Search a file for a pattern using full regular expressions.
grep will not always have as complete of functionality for regex.