if last 4 file size of a directory are same with each other then exit otheriwse continue

Question

Please give me any shell bash script that will help me doing following task:

if last added 4 file size of a directory are same with each other then exit other wise continue

Example :

ls -l $dir_path | awk '{print $5}' | tail -4

if the 4 printed values are same to each other then exit otherwise continue.

In order to get help with you script writing abilities, please show us what you tried and give details on why it doesn't work. — Julie Pelletier, Jul 22 '16 at 12:29

Stéphane Chazelas · Answer 1 · 2016-07-22T13:28:34.357

1

zsh -c 'zmodload zsh/stat
  [[ $(zstat -N +size -- *(.om[1,4])) =~ $'\''(.*)\n\\1\n\\1\n\\1'\'' ]]' && exit

Would exit if the 4 newest non-hidden regular files in the current directory all have the same size.

On a GNU system, you could also do:

find . -maxdepth 1 ! -name '.*' -type f -printf '%T@ %s\n' |
  sort -rn |
  awk 'NR == 1 {v = $0}; v != $0 {exit}; NR == 4 {exit 1}' || exit

POSIXly:

ls -tnq -- "$dir_path" |
  awk '!/^-/ {next}
       n++ == 0 {v = $5}
       v != $5 {exit}
       n == 4 {exit 1}' || exit

If like in your own approach, instead of the 4 newest ones, you want the last 4 (regardless of whether they're regular files or symlinks or sockets...) in the ls output (which is an alphabetically sorted list), you can do (still POSIXly):

ls -rnq -- "$dir_path" |
  awk 'NR == 1 {next}
       NR == 2 {v = $5}
       v != $5 {exit}
       NR > 4 {exit 1}' || exit

edited Jul 22 '16 at 13:28

answered Jul 22 '16 at 12:36

Stéphane Chazelas

544,893

2

OP wants bash, not zsh... – user Jul 22 '16 at 12:41
@MichaelKjörling well spotted, updated. – Stéphane Chazelas Jul 22 '16 at 12:51
Well, that's one way of solving that... :-) – user Jul 22 '16 at 13:07

score 0 · Answer 2 · edited Apr 13 '17 at 12:36

0

Use ls -c to sort by ctime, and uniq to see if they're the same.

ls -crntq | tail -4 | awk '{print $5}' | uniq -c | grep -q "^\s*4\s" && exit

edited Apr 13 '17 at 12:36

Community

1

answered Jul 22 '16 at 13:26

JigglyNaga

7,886

Note that ls -s gives the file disk usage, not the file size. – Stéphane Chazelas Jul 22 '16 at 13:47
You'd want to pass the -q option to avoid problems with filenames containing newline characters. – Stéphane Chazelas Jul 22 '16 at 13:48
@StéphaneChazelas Bah, I'll have to use the longer output for the size-in-bytes. My version of ls (GNU coreutils 8.21) had already changed the newlines to ?, so -q made no difference, but I'll include that for completeness. – JigglyNaga Jul 22 '16 at 14:07
Without -q, the newline is only turned to ? when the output doesn't go to a terminal, so typically, not when fed to tail via a pipe. – Stéphane Chazelas Jul 22 '16 at 14:18

if last 4 file size of a directory are same with each other then exit otheriwse continue

2 Answers2