Question

Write single linux commands for each question.

2. Find every file ends with “.py” or “.txt” or “.cpp” from your root directory, and list the detail of each file.

3. Find every line that contains two or more space in every file in “Folder1” include subdirectory.

4. Find every line that contains two or more “<<” symbol in “Folder2” include subdirectory.

5. Find every line that contains parentheses inside parentheses in “Folder3” include subdirectory, such as print(type(6*2)).

6. Find every line that contains at least two digits in folder “Folder1”, “Folder2” and “Folder3” include subdirectory. The two digits can be two separate digit, such as “1.5” or “1 and 2”.

7. Find every line that start with “}” or ends with “{” in “Folder2” include subdirectory. Example: “int main(){” or “}”.

8. Find every line that contains any pair of repeated words in folder “Folder1”, “Folder2” and “Folder3” include subdirectory. Example: a + a, b b, c d c d. (The command should be able to find the ‘c = a + “ ” + b’)

9. List every filename contains at least two digits from folder “Folder1”, “Folder2” and “Folder3” include subdirectory.

10. List every filename contains a number that greater than 11 and less than 22 from folder “Folder1”, “Folder2” and “Folder3” include subdirectory.

Answer 1

2.

find . -iregex '.*\.\(py\|cpp\|txt\)$' -ls

the iregex command is used for regular expression matching ignoring the case and ls is used to display the details of the files. The regular expression for a file with some extension say .a would be " *.a ".

Please make sure that the spaces are as written in the answer when the command is executed.

3.

grep -r '* * *' /Folder1

the -r flag is used to search recursively in the directory (search the current directory and all sub directories) " * * * " is the regular expression for text that has 2 or more spaces.

4.

grep -r '*<<*<<*' /Folder2

the -r flag is used to search recursively in the directory (search the current directory and all sub directories) and " *<<*<<* " is the regular expression for text that has 2 or more << symbols.

5. 

grep -r '(*(*)*)' /Folder2

the -r flag is used to search recursively in the directory (search the current directory and all sub directories) and "(*(*)*)" is the regular expression for text that has parenthesis inside parenthesis.

6.

grep -r '*[0-9]*[0-9]*' /Folder1/ /Folder2/ /Folder3/

The multiple folders to search in are specified this way and all other stuff is same as above.

7.

grep -r '(^{*)|(*}$)' /Folder2

The regular expression for this problem consists of ^ and $ which are the start and end symbols respectively. Rest is same as above.

9.

find / -iregex '*[0-9]*[0-9]*\.*' /Folder1/ /Folder2/ /Folder3/

The explanations are same as part 2. the regular expression is for two digits and I have added a \.* at the end of the regular expression so that the two numbers are in the file name and not in the extension.

10.

find / -iregex '*\(1*[2-9]*\|21\)*\.*' /Folder1/ /Folder2/ /Folder3/

The ecplanation is same as part 2 and part 9.