UNIX for Dummies Questions & Answers

i want to know how to do a few things using unix commands.

firstly say I have a .txt file that contains random lines like

Hello
Goodbye
I'm tired
5
74

using the grep command how can I get a list of lines that contain ONLY digits?

also using pipes to combine ls and grep commands how do I list all directories in the current directory that have rwx permissions for the user, group and other?

i was thinking its grep "rwxrwxrwx" | ls -l but that doesn't seem to be working?

how do I use the ls command to list the files in a directory that aren't certain files (for example list all the files that aren't .txt files) ?

thanks for any help.

Welcome to the forums

I will help with the first question

Code:

grep "[0-9][0-9]*" filename

For others, you need to take a look at the threads already posted

- i was thinking its grep "rwxrwxrwx" | ls -l but that doesn't seem to be working?

instead of using grep rwxrwxrwx | ls -l .... use

Code:

ls -l | grep rwxrwxrwx

It should work.

- how do I use the ls command to list the files in a directory that aren't certain files (for example list all the files that aren't .txt files) ?

use option -v with grep which selects non-matching lines.

Code:

ls -l | grep -v *.txt

Code:

$ cat asd
Hello
23Goodbye2324
32453
67 87 _
@xfsf
I'm tired
5
2424324
74

Match only digits: 

$ grep '^[0-9]*$' asd
32453
5
2424324
74

Something like:

Code:

 ls -l | grep '^drwxrwxrwx' | cut -d" " -f8

Regards

thanks guys