UNIX for Dummies Questions & Answers

Hi all



Can anyone advise how do I use ls to do a selective amd sorted listing of file that I want to have as below?

Am looking for files that are named as log_<nnnn>.txt, where <nnnn> are numeric, i.e. I want to have a listing sorted from the newest to the oldest of files that starts with log_ and with a .txt extension and the characters in between these two can only be numeric, example log_1.txt, log_234.txt, log_222.txt etc.

I want to exclude files like log_9ab.txt, log_a9b.txt., log_99a.txt

I thought I can get away with doing

Code:

ls -1tr log_[0-9][0-9]*.xml

but unfortunately the * list also files like log_99a.txt.

I want to be able to only list files where the characters in between log_ and .txt are numeric, unfortunately, sometimes, there can be 2, 3 or 5 numeric characters.

Any advise will be much appreciated. Thanks in advance.

ls -1tr log_[0-9][0-9]* works as expected on my RHEL GNU-Bash.

An alternative, try this:

Code:

ls -1tr | grep 'log_[0-9][0-9]*.txt'

Try:

Code:

ls -1tr log_[0-9].xml  log_[0-9][0-9].xml  log_[0-9][0-9][0-9].xml  log_[0-9][0-9][0-9][0-9].xml  log_[0-9][0-9][0-9][0-9][0-9].xml 2>/dev/null

Less exact, but you might get away with:

Code:

ls -1tr log_*[0-9].xml

Try:

Code:

ls | egrep 'log_[0-9]+\.xml'

Code:

ls log_+([0-9]).txt

(ksh on RHEL 5.4)

ksh93-style extended globbing also works in recent versions of bash after issuing:

Code:

shopt -s extglob

Thanks. That one works so far on :Linux. Hope the same thing works on Solaris.

---------- Post updated at 06:27 AM ---------- Previous update was at 06:18 AM ----------

Thanks to everyone who responded.

So far, yazu's suggestion is what am trialing out.

Code:

ls | egrep 'log_[0-9]+\.xml'

Also found the link below useful, in case egrep does not function like it used to on other *nixes or on others where egrep is not available.

https://www.unix.com/shell-programmin...ric-value.html

FYI, my other chosen alternative which is using awk if egrep is not available is as below. Any awk expert around to make it "shorter"

Code:

ls -1tr *.xml | awk -F. '{ print $1 }' | awk -F_ '{ print $2 }' | awk '/^[0-9]+$/' | awk '{ print "log_"$1".xml" }'

or for .txt files

ls -1tr *.txt | awk -F. '{ print $1 }' | awk -F_ '{ print $2 }' | awk '/^[0-9]+$/' | awk '{ print "log_"$1".xml" }'

Thanks again everyone. Very much appreciated.