[root@syslog-ng ~] # cd /opt/backup/ [root@syslog-ng backup] # ls -l total 68 drwxr-xr-x. 2 root root 4096 Jul 11 14:48 20180626 drwxr-xr-x. 2 root root 4096 Jul 11 14:48 20180627 drwxr-xr-x. 2 root root 4096 Jul 11 14:48 20180628 drwxr-xr-x. 2 root root 4096 Jul 11 14:48 20180629 drwxr-xr-x. 2 root root 4096 Jul 11 14:48 20180630 drwxr-xr-x. 2 root root 4096 Jul 11 14:48 20180631 drwxr-xr-x. 2 root root 4096 Jul 11 14:48 20180701 drwxr-xr-x. 2 root root 4096 Jul 11 14:48 20180702 drwxr-xr-x. 2 root root 4096 Jul 11 14:48 20180703 drwxr-xr-x. 2 root root 4096 Jul 11 14:48 20180704 drwxr-xr-x. 2 root root 4096 Jul 11 14:48 20180705 drwxr-xr-x. 2 root root 4096 Jul 11 14:48 20180706 drwxr-xr-x. 2 root root 4096 Jul 11 14:48 20180707 drwxr-xr-x. 2 root root 4096 Jul 11 14:48 20180708 drwxr-xr-x. 2 root root 4096 Jul 11 14:48 20180709 drwxr-xr-x. 2 root root 4096 Jul 11 14:48 20180710 drwxr-xr-x. 2 root root 4096 Jul 11 14:48 20180711 [root@syslog-ng backup] # /bin/ls -l |grep "^d" drwxr-xr-x. 2 root root 4096 Jul 11 14:48 20180626 drwxr-xr-x. 2 root root 4096 Jul 11 14:48 20180627 drwxr-xr-x. 2 root root 4096 Jul 11 14:48 20180628 drwxr-xr-x. 2 root root 4096 Jul 11 14:48 20180629 drwxr-xr-x. 2 root root 4096 Jul 11 14:48 20180630 drwxr-xr-x. 2 root root 4096 Jul 11 14:48 20180631 drwxr-xr-x. 2 root root 4096 Jul 11 14:48 20180701 drwxr-xr-x. 2 root root 4096 Jul 11 14:48 20180702 drwxr-xr-x. 2 root root 4096 Jul 11 14:48 20180703 drwxr-xr-x. 2 root root 4096 Jul 11 14:48 20180704 drwxr-xr-x. 2 root root 4096 Jul 11 14:48 20180705 drwxr-xr-x. 2 root root 4096 Jul 11 14:48 20180706 drwxr-xr-x. 2 root root 4096 Jul 11 14:48 20180707 drwxr-xr-x. 2 root root 4096 Jul 11 14:48 20180708 drwxr-xr-x. 2 root root 4096 Jul 11 14:48 20180709 drwxr-xr-x. 2 root root 4096 Jul 11 14:48 20180710 drwxr-xr-x. 2 root root 4096 Jul 11 14:48 20180711 [root@syslog-ng backup] # /bin/ls -l |grep "^d"|awk '{print $9}' 20180626 20180627 20180628 20180629 20180630 20180631 20180701 20180702 20180703 20180704 20180705 20180706 20180707 20180708 20180709 20180710 20180711 [root@syslog-ng backup] # /bin/ls -l |grep "^d"|awk '{print $9}'|wc -l 17 [root@syslog-ng backup] # /usr/bin/expr 17 - 3 14 |