Awk not rendering any result

Question

My goal is to get the file created in the current month in a directory.

It seems that the command is correct but not rendering any result:

Date=`date '+%b'`

echo $Date
Oct

ls -l | awk -v d="$Date" '/d/ {print $NF}'

You have not explained what you really want. This is a broken code. — Valentin Bajrami, Oct 15 '13 at 12:09
@dchirikov Agreed, or even -ctime to catch when file attributes have changed. — Joseph R., Oct 15 '13 at 12:43

dchirikov · Answer 1 · 2013-10-15T13:52:17.020

7

You should use it this way:

ls -l | awk -v d="$Date" '$0 ~ d {print $NF}'

Explanation is here

But may be it's better to use find in your script.

find . -maxdepth 1 -type f -daystart -ctime -`date "+%d"`

If you have classic awk instead of gawk:

find * -prune -type f -cmin -`date '+%d %H %M' | awk '{print ($1*24+$2)*60+$3}'`

edited Oct 15 '13 at 13:52

answered Oct 15 '13 at 12:15

dchirikov

3,888

+1 I hope you don't mind, I edited your link so that it points directly to the relevant section instead of the TOC. – Joseph R. Oct 15 '13 at 13:00
Since I am using AIX 6.1 machine the flags such as -maxdepth and -daystart are not available. – Ram Oct 15 '13 at 13:34
Ok. I've added an update. Hope it helps. – dchirikov Oct 15 '13 at 13:52

score 2 · Accepted Answer · edited Jun 11 '20 at 12:04

2

The problem here is that awk has no way of telling that the d inside the pattern is meant to represent the variable of that name: awk is trying to match a literal d. You can make use of parameter expansion instead:

ls -l | awk "/$Date/ {print \$NF}"

That said, two things to note:

The time listed in ls -l output is the timestamp: the last time the file was modified, not created. File creation times are unreliable at best and unavailable at worst.
You shouldn't parse the output of ls

Use find instead, as in dchirikov's answer.

edited Jun 11 '20 at 12:04

Community

1

answered Oct 15 '13 at 12:18

Joseph R.

39,549

-v tells awk to use environmental variable – dchirikov Oct 15 '13 at 12:24
@dchirikov As far as I know, -v is used to assign variables localized to awk not obtain variables from your current environment. – Joseph R. Oct 15 '13 at 12:42
2

Right. Environment variables can be accessed through the ENVIRON array. So if you previously export Date, then ls -l | awk '$0 ~ ENVIRON["Date"] {print $NF}' will also work. – manatwork Oct 15 '13 at 12:48
yep! ENVIRON of course. And -v is for shell variables. – dchirikov Oct 15 '13 at 12:57
1

@Ram Glad I helped. I believe dchirikov's answer was better though. Stay away from the output of ls unless you're parsing it with your eyes. – Joseph R. Oct 15 '13 at 14:48
Solutions using ls and awk mis-fire on files that contain the current month abbreviation in the name, e.g. "Octopus", "Nova", "Decimal", etc.
Solutions using ls and awk fail to print the full name of files that contain blanks or newlines in the name, e.g. "my file".
As has been said: do not parse the output of ls. Use find.

Ian D. Allen

Oct 15 '13 at 15:00

Awk not rendering any result

2 Answers2