sort nested directories by last modified using find

Using ls -lt to sort a file listing by last modified time is simple and easy. If you have a large directory tree with tens of thousands of directories, using find with some massaging might be the way to go. In this example there is a directory with many directories in a tree like this:

./1
./1/1
./1/1/1
./1/1/2
./1/2
./1/2/3
./2
./2/3
./2/3/4
./2/3/5
./2/3/7
./2/3/8

we are interested in the 3rd level directory and getting a list of which ones were most recently modified

# find . -mindepth 3 -maxdepth 3 -ls | awk '$10 !~ /^20[01]/' | sed -e 's/:/ /' | sort -k8,8M -nk9,9n -nk10 -nk11 | awk '{print $12" "$8" "$9" "$10":"$11}'| column -t | tail -10

We start by finding only 3rd level directories with extended listings (there are no files at this level, so -type d is unnecessary). Then use awk to only print directories that have been modified this year (i.e. anything with a year like 200* or 201* instead of a hour:minute in column 10). Replace the time colon HH:MM so that we can sort by minute after we sort by hour. Then rearrange the columns, add back the hour:minute colon, run it through column to get nice columns, then get the last 10 results.

./586/1586/1311586  Sep  16  16:11
./980/6980/2326980  Sep  16  16:18
./616/3616/513616   Sep  16  16:20
./133/9133/2119133  Sep  16  16:21
./422/6422/2106422  Sep  16  16:24
./566/6566/2326566  Sep  16  16:46
./672/672/2310672   Sep  16  16:51
./680/680/2290680   Sep  16  17:42
./573/5573/2325573  Sep  16  17:47
./106/1106/2321106  Sep  16  17:49
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diff command outputs, not files

You can easily diff the output of commands instead of files. In this case hexdump prints thousands of lines, but I’m only interested in the difference:

# diff <(hexdump file1.bin) <(hexdump file2.bin)
1,2c1,2
< 0000000 6a49 b610 0000 0000 5733 7261 4465 4243
< 0000010 0000 0000 0001 0000 9006 4e0b 0b28 000f
---
> 0000000 6a49 b616 0000 0000 5733 7261 4465 4243
> 0000010 0000 0000 0001 0000 9006 4e11 0b28 000f

Run the hexdump in subshell using parenthesis, then redirect the output back to diff. I’m only interested in the 2 pieces that are different for each binary file:

# for i in `ls *.bin | sort -nk1.7`; do echo -n "$i: "; hexdump -C $i | grep '33 57 61 72 65 44\|4e 28 0b 0f 00' | awk '{if(NR==1) print $4;if(NR==2) print $12}' | paste - -; done | column -t 2>/dev/null
file0.bin:   1a  15
file1.bin:   19  14
file2.bin:   18  13
file3.bin:   17  12
file4.bin:   16  11
file5.bin:   15  10
file6.bin:   14  0f
file8.bin:   12  0d
file9.bin:   11  0c
file10.bin:  10  0b
file12.bin:  0e  09
file13.bin:  0d  08
file14.bin:  0f  0a
file15.bin:  0b  06
file16.bin:  0a  05
file17.bin:  09  04
file18.bin:  08  03
file19.bin:  07  02
file20.bin:  06  01
file21.bin:  05  00
file22.bin:  0c  07
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dhcpd lease information sorted by date and time

When looking on a pxe boot install server, you can see what the newest clients were to boot. If you don’t have KVM access on new servers to be installed, just look at the newest lease info, and make an educated guess about which new one to login to the auto-installer environment (preseed) via ssh.

Here’s a snippet from the leases file:

lease 10.101.40.85 {
  starts 3 2013/05/15 19:54:36;
  ends 3 2013/05/15 20:54:36;
  cltt 3 2013/05/15 19:54:36;
  binding state active;
  next binding state free;
  hardware ethernet 00:30:48:5c:cf:34;
  uid "\001\0000H\\\3174";
}

And after some parsing:

# cat /var/lib/dhcp/dhcpd.leases | grep -e lease -e hardware -e start -e end | grep -v format | grep -v written | sed -e '/start/s/\// /g' -e 's/;//g' -e '/starts/s/:/ /g' | paste - - - - | awk '{print $2" "$18" "$6" "$7" "$8" "$9" "$10" "$11" "$14" "$15}' | sort -k 3,3n -k 4,4n -k 5,5n -k 6,6n -k 7,7n -k 8,8n | awk '{print $1" "$2" "$3"/"$4"/"$5" "$6":"$7":"$8" "$9" "$10}' | column -t


10.101.40.127  00:1e:68:9a:e5:ac  2013/04/26  22:02:58  2013/04/26  23:02:58
10.101.40.129  00:1e:68:9a:e5:ac  2013/04/26  23:10:01  2013/04/27  00:10:01
10.101.40.122  00:1e:68:9a:e5:ac  2013/04/26  23:27:57  2013/04/26  23:30:42
10.101.40.118  00:1e:68:9a:ee:69  2013/05/14  16:21:28  2013/05/14  17:21:28
10.101.40.85   00:30:48:5c:cf:34  2013/05/14  16:54:43  2013/05/14  17:54:43
10.101.40.118  00:1e:68:9a:ee:69  2013/05/14  17:14:04  2013/05/14  18:14:04
10.101.40.85   00:30:48:5c:cf:34  2013/05/14  17:24:43  2013/05/14  18:24:43
10.101.40.85   00:30:48:5c:cf:34  2013/05/14  17:54:42  2013/05/14  18:54:42
#
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