[SOLVED] Can't use grep to find files modified within 10 hours ago.

andrew.comly · 09-13-2015, 09:12 AM

I am currently reading the online book Bash Beginners' Guide (http://www.tldp.org/LDP/Bash-Beginne...ect_04_05.html), and am trying to complete Chapter 4.5. Exercises. Question 7 asks:
Make a list of files in your home directory that were changed less that 10 hours ago, using grep, but leave out directories.

I really think this question is strange, since no matter how many times I look at the manpages for grep, it simply never mentions modification time. However after doing some research on the web, I can now find all the files(not documents) changed less than 10 hours ago via "find":

Code:

find /media/a/LG/AC/ -maxdepth 1 -type f -mmin -600

The part of this questions that tells people to leave out directories isn't hard, since whenever you want to exclude something you can just find everything except for <yourString> via "grep -v", where "v" is short for inverse.

However, the part about "changed less that 10 hours ago" just doesn't seem plausible. Did the author mix up the word "grep" and "find"? Can "grep" be used to find a file modified within a certain amount of time?

NevemTeve · 09-13-2015, 09:26 AM

Dunno, maybe the solution might include 'ls -l' and 'date'

goumba · 09-13-2015, 10:30 AM

Use find with the option that mimics ls -l

find -ls

ntubski · 09-13-2015, 11:43 AM

Quote:

Originally Posted by andrew.comly

However after doing some research on the web, I can now find all the files(not documents) changed less than 10 hours ago via "find":

I think "find" is the correct tool for this, the exercise writer made a mistake.

Quote:

The part of this questions that tells people to leave out directories isn't hard, since whenever you want to exclude something you can just find everything except for <yourString> via "grep -v", where "v" is short for inverse.

But see also grep's --directories option:

Quote:

-d action
--directories=action

If an input file is a directory, use action to process it. By default, action is ‘read’, which means that directories are read just as if they were ordinary files (some operating systems and file systems disallow this, and will cause grep to print error messages for every directory or silently skip them). If action is ‘skip’, directories are silently skipped. If action is ‘recurse’, grep reads all files under each directory, recursively, following command-line symbolic links and skipping other symlinks; this is equivalent to the -r option.

HMW · 09-13-2015, 11:44 AM

Quote:

Originally Posted by andrew.comly

However, the part about "changed less that 10 hours ago" just doesn't seem plausible. Did the author mix up the word "grep" and "find"?

I applaud you for not trying to use a screwdriver for hammering a nail. You are right of course, nobody would use grep for that, and I think it's a silly exercise. However, you are not alone. Read more at SO:
http://stackoverflow.com/questions/1...s-ago#17509507

Best regards,
HMW

andrew.comly · 09-26-2015, 10:43 PM

The exercise is truly defective.

Anyway, what's important is that I have learned how to make a list of files in a users home directory that were changed less that 10 hours ago, leaving out directories.