Grep Command Issue

Hi All,

I am new to unix and is trying with a few things. I am encountering the below error when executing a command like grep -B 2 'string' sample.txt

grep: illegal option -- B
usage: grep [-E|-F] [-c|-l|-q] [-bhinsvx] -e pattern_list...
[-f pattern_file...] [file...]
usage: grep [-E|-F] [-c|-l|-q] [-bhinsvx] [-e pattern_list...]
-f pattern_file... [file...]
usage: grep [-E|-F] [-c|-l|-q] [-bhinsvx] pattern [file...]

Can anybody tell me the reason for this error.

Thanks in advance and wishing you all a very happy new year.

 

use lowercase b

grep -b 2 'string' sample.txt

 

grep -B 2 ... should work. Worked on my Mac [terminal] using darwin. did you check the man pages on your system?

Q...

 

Unlike Mac/PC, Unix is always case sensitive. This is also true for directory name, database names, tables names, etc..

 

Partial man page for grep:

       -B NUM, --before-context=NUM
              Print  NUM  lines  of  leading  context  before  matching lines.
              Places  a  line  containing  --  between  contiguous  groups  of
              matches.

       -C NUM, --context=NUM
              Print  NUM lines of output context.  Places a line containing --
              between contiguous groups of matches.

       -b, --byte-offset
              Print the byte offset within the input file before each line  of
              output.
:

Code (markup):

I took case sensitivity into consideration.


Q...

 

grep -B is not working for me in only one server. On other servers it is working fine. So i doubt if we have to install anything else for this option to work. Anybody has any idea.

 

what is the output of "grep -V"

 

Hmmm.... I will look into this...