Closed. This question needs details or clarity. It is not currently accepting answers.
Want to improve this question? Add details and clarify the problem by editing this post.
Closed 1 year ago.
This post was edited and submitted for review 1 year ago and failed to reopen the post:
Original close reason(s) were not resolved
Improve this question
I have a file which contains below information-
SOURCE "defrust"
DESIGN "2_3"
SYSTEM SPICE
NETLIST SOURCE
NETS "NONE"
//NETS "NONE"
//VARIABLE "cell2"
DESIGN "hello one"
How can i use unix commands to delete full lines which are starting from SOURCE ,DESIGN and //
output be somewhat like-
SYSTEM SPICE
NETLIST SOURCE
NETS "NONE"
thanks in advance
Use this Perl one-liner:
perl -i.bak -ne 'print if !m{^(SOURCE|DESIGN|//)}' file_name
The Perl one-liner uses these command line flags:
-e : Tells Perl to look for code in-line, instead of in a file.
-n : Loop over the input one line at a time, assigning it to $_ by default.
-i.bak : Edit input files in-place (overwrite the input file). Before overwriting, save a backup copy of the original file by appending to its name the extension .bak.
^ : beginning of the line in regex.
SEE ALSO:
perldoc perlrun: how to execute the Perl interpreter: command line switches
perldoc perlre: Perl regular expressions (regexes)
Related
Closed. This question needs debugging details. It is not currently accepting answers.
Edit the question to include desired behavior, a specific problem or error, and the shortest code necessary to reproduce the problem. This will help others answer the question.
Closed 8 years ago.
Improve this question
I have a file with millions of lines.And each line ends with a format say "XXX:some value" .. I want to grep only this word "XXX:some value" from each line and put it in a separate file.How can i achieve this using grep command?
PS: "some value" can be any string
To get last n characters of each line using awk:
cat file
asdf
asdfg
asdfgh
awk -vn=2 '{print substr($0,length($0)-n+1)}'
df
fg
gh
Or do you like to get data after XXX, then do:
echo "here is my line XXX:22" | awk -F"XXX:" '{print $2}'
22
Use the -o flag:
grep -o 'XXX:.*' <input >output
You could just use grep as below:
grep -ow 'XXX:some value' myfile.txt > patternMatched.txt
Closed. This question needs to be more focused. It is not currently accepting answers.
Want to improve this question? Update the question so it focuses on one problem only by editing this post.
Closed 8 years ago.
Improve this question
I have a text file in which i have 17000 lines, example:
another instance started
another instance started
instance not started
bss instance started
like this.
I have to find the number of times the word 'another' is in printed in the above example my output should be 2. I need shell script command for the above example. Can any one help me with shell coding or command?
First you should try to search harder, the answer can be found easily.
Second:
grep -c another yourfilepath
Just use good old grep.
grep -c 'word' file
\<another\> is a word boundary and it won't match abcanother or anotherxyz etc.
grep -o '\<another\>' file.txt | wc -l
grep -c flip article.txt
10
See http://www.linuxjournal.com/article/2384
and http://www.cyberciti.biz/faq/grep-regular-expressions/
Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers.
This question does not appear to be about a specific programming problem, a software algorithm, or software tools primarily used by programmers. If you believe the question would be on-topic on another Stack Exchange site, you can leave a comment to explain where the question may be able to be answered.
Closed 8 years ago.
Improve this question
I would like to grep a pattern from multiple log files which are being constantly updated by some processes and tail the output of this grep continuosly.
Below command doesnt work and I get
tail: warning: following standard input indefinitely is ineffective
tail -f | grep --line-buffered "Search this: " /var/links/proc2/id/myprocess*/Daily/myprocess*.log
Can someone help sort this out?
You should have a look at multitail tool (Install using sudo apt-get install multitail)
In short, with multitail, you need to use the --mergeall flag for viewing output of all in one place
multitail --mergeall /var/links/proc2/id/myprocess*/Daily/myprocess*.log | grep --line-buffered "Search this: "
You can do the same without using grep
multitail -E "Search this: " --mergeall /var/links/proc2/id/myprocess*/Daily/myprocess*.log
To view the output individually using multitail, this will give the filename as well.
multitail -E "Search this: " /var/links/proc2/id/myprocess*/Daily/myprocess*.log
the mistake is that you give the files to the grep command and not the tail.
the tail -f needs to get the files as input. try:
tail -f /var/links/proc2/id/myprocess*/Daily/myprocess*.log | grep --line-buffered "Search this: "
to get also the file names (however it will not be like grep output it is):
tail /var/links/proc2/id/myprocess*/Daily/myprocess*.log | grep --line-buffered -e'^==> .* <==$' -e'Search this: '
This is an interesting question and the simple answer should be: Use the prefix switch with tail, but unfortunately this is currently not implemented in most versions of tail.
As I see it, you have two options: adapt the standard tools to the task (see Udys answer) or write your own tool with your favorite scripting/programming language.
Below is one way you could do it with the File::Tail::Multi module for perl. Note that you may need to install the module from CPAN (cpan -i File::Tail::Multi).
Save the following script e.g. mtail to your executable path and make the script executable.
#!/usr/bin/env perl
use File::Tail::Multi;
$| = 1; # Enable autoflush
$tail = File::Tail::Multi->new(RemoveDuplicate => 0,
OutputPrefix => 'f',
Files => \#ARGV);
while(1) { $tail->read; $tail->print; sleep 2 }
Change OutputPrefix to 'p' if you prefer full path prefixes.
Run it like this:
mtail /var/links/proc2/id/myprocess*/Daily/myprocess*.log | grep --line-buffered "Search this: "
You do not need to specify --line-buffered when grep is the last command, so this is sufficient:
mtail /var/links/proc2/id/myprocess*/Daily/myprocess*.log | grep "Search this: "
Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers.
Closed 8 years ago.
This question appears to be off-topic because it lacks sufficient information to diagnose the problem. Describe your problem in more detail or include a minimal example in the question itself.
Questions must demonstrate a minimal understanding of the problem being solved. Tell us what you've tried to do, why it didn't work, and how it should work. See also: Stack Overflow question checklist
Improve this question
Using UNIX Scripting it is possible to remove all the firsts characters from a file till a specific character is found ?
I have a file with "garbage" at the beginning. I want to remove that "garbage, meaning that all the character till the first "{" must be removed. How can I do this ?
cat file.txt | grep -A 1000000000 '{' | sed '1 s/^[^{]*//'
This will print the changed contents (i. e. without the garbage) to stdout. You can redirect this using > outfile.txt appended to the command:
cat file.txt | grep -A 1000000000 '{' | sed '1 s/^[^{]*//' > outfile.txt
And if you want to change the file in-place, this can be done by renaming the outfile.txt to the original name file.txt afterwards:
mv outfile.txt file.txt
Closed. This question is off-topic. It is not currently accepting answers.
Want to improve this question? Update the question so it's on-topic for Stack Overflow.
Closed 9 years ago.
Improve this question
This is probably a very stupid question, but is it possible that files can be deleted with the "mv" command?
I'm asking because I when I was attempting to move a file up to its parent directory, I accidentally typed one "." too many and now I can't find my file.
So instead of:
$ mv myfile.txt ..
I had put:
$ mv myfile.txt ...
Now my file is gone. Did I delete it accidentally, and is it possible to get it back at all?
Thanks!
Your file has been renamed to "..." do an ls -a to see dot files.
Try mv ... ../myfile.txt to get do what you originally wanted.
you file is now named as ..., check it with ls -al in your current dir.
On UNIX systems, file names starting with a dot are hidden from directory listings by default.
ls -lA
will display dot files.
You can rename the file back
mv ... myfile.txt
Your file is now called ... and is not visible thru the simple ls command.
Use ls -a to make "system" files (starting with a dot) visible or rename it back mv ... your_file.
And to answer the title-question:
Yes and no.
It' s not possible, but moving the file to /dev/null will delete it as well. :D