Question

3.0.3 Questions: Using patterns wtih grep Provide the grep commands for the following searches in the file /usr/share/common-licenses/GPL-3 1. All lines that contain words that begin with a capital letter. 3 2. All text of any length that is a parenthetical statement (i.e., in paren- thesis). 3. Any line in the file that begins with a capital letter and ends with a period. 4. Any line in the file that contains the strings "GPL" or "General Public License".

Using Linux commands grep

Answer 1

CODE

[1] grep '^[A-Z]' /usr/share/common-licenses/GPL-3

[2]   grep -Po '(?<=\().*?(?=\))' /usr/share/common-licenses/GPL-3

[3] grep '^[A-Z].*\.$' /usr/share/common-licenses/GPL-3

[4] grep 'GPL\|General\sPublic\sLicense' /usr/share/common-licenses/GPL-3

OUTPUT

1.  

root@exploitech:-# grep '^[A-Z]' /usr/share/common-licenses/GPL-3 GNU General Public License for most of our software; it applies also to States should not allow patents to restrict development and use of License. Each licensee is addressed as "you". "Licensees" and Component, and (b) serves only to enable use of the work with that Major Component, or to implement a Standard Interface for which an System Libraries, or general-purpose tools or generally available free Source. User Product is transferred to the recipient in perpetuity or for a Corresponding Source conveyed under this section must be accompanied License by making exceptions from one or more of its conditions. Additional permissions that are applicable to the entire Program shall License, you may add to a covered work material governed by the terms Corresponding Source of the work from the predecessor in interest, if License of the Program or a work on which the Program is based. The License and any other pertinent obligations, then as a consequence you may License would be to refrain entirely from conveying the Program. License will continue to apply to the part which is the covered work, Program specifies that a certain numbered version of the GNU General Public License "or any later version" applies to it, you have the Foundation. If the Program does not specify a version number of the GNU General Public License, you may choose any version ever published APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION. WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. Program, unless a warranty or assumption of liability accompanies a Also add information on how to contact you by electronic and paper mail. The hypothetical commands `show w' and `show c' should show the appropriate For more information on this, and how to apply and follow the GNU GPL, see Public License instead of this License. But first, please read root@exploitech:-# 1

2.  

root@exploitech:-# grep - Po '(?<=\(.*?(?=))' /usr/share/common-licenses/GPL-3 C i 2 with or without modification i 2 а b kernel, window system, and so on if any including a physical distribution medium including a physical distribution medium i 2 gratis or for a charge operated by you or a third party 2 regardless of how the transaction is characterized а b for any work including a cross-claim or counterclaim in a lawsuit 1 2 3 a or copies made from those copies b с at your option C if you work as a programmer root@exploitech:-#

3.


root@exploitech:-# grep '^[A-Z].*\.$' /usr/share/common-licenses/GPL-3 Source. License by making exceptions from one or more of its conditions. License would be to refrain entirely from conveying the Program. ALL NECESSARY SERVICING, REPAIR OR CORRECTION. SUCH DAMAGES. Also add information on how to contact you by electronic and paper mail. root@exploitech:~#


4.

root@exploitech:-# grep 'GPL\| General\sPublic\sLicense' /usr/share/common-licenses/GPL-3 The GNU General Public License is a free, copyleft license for the GNU General Public License is intended to guarantee your freedom to GNU General Public License for most of our software; it applies also to price. Our General Public Licenses are designed to make sure that you Developers that use the GNU GPL protect your rights with two steps: For the developers' and authors' protection, the GPL clearly explains authors' sake, the GPL requires that modified versions be marked as have designed this version of the GPL to prohibit the practice for those of the GPL, as needed to protect the freedom of users. make it effectively proprietary. To prevent this, the GPL assures that "This License" refers to version 3 of the GNU General Public License. 13. Use with the GNU Affero General Public License. under version 3 of the GNU Affero General Public License into a single but the special requirements of the GNU Affero General Public License, the GNU General Public License from time to time. Such new versions will GNU General Public License, you may choose any version ever published versions of the GNU General Public License can be used, that proxy's it under the terms of the GNU General Public License as published by GNU General Public License for more details. You should have received a copy of the GNU General Public License parts of the General Public License. Of course, your program's commands For more information on this, and how to apply and follow the GNU GPL, see The GNU General Public License does not permit incorporating your program root@exploitech:-#


EXPLANATION

The grep scans a document for a specific pattern of characters, and shows all lines that contain that pattern. The pattern that is looked/searched in the file is called regular expression.

Syntax - grep [options] pattern [files]

[1] grep '^[A-Z]' /usr/share/common-licenses/GPL-3​​​​​​​

The ^ regular expression pattern indicates the beginning of a line. This can be utilized in grep to match the lines which start with the given string or example. In our case we want to get the lines that will start with uppercase letter only. So we used ^[A-Z].

[2]   grep -Po '(?<=\().*?(?=\))' /usr/share/common-licenses/GPL-3
-P option Interpret PATTERN as a Perl regular expression and -o : Print only the matched parts of a matching line
(?<=\().*?(?=\))
​​​​​​​This will look for the opening bracket ( and then ignores it, then prints all the non-close-parenthesis characters that follow.

[3] grep '^[A-Z].*\.$' /usr/share/common-licenses/GPL-3

We can combine( perform and operation) two regular expression by using .*

^[A-Z] this will return words start with capital letters

\.$  this will return words end with . (Period)

[4] grep 'GPL\|General\sPublic\sLicense' /usr/share/common-licenses/GPL-3

For or we used \| or operator in regular expression. for space, we used \s regular expression.