How to clean log files in Linux

 

Reference from :https://support.hostway.com/hc/en-us/articles/360001972270-How-to-clean-log-files-in-Linux

hydev@localhost ~]$ du -h /var/log/

du: cannot read directory ‘/var/log/sssd’: Permission denied

0 /var/log/sssd

du: cannot read directory ‘/var/log/samba’: Permission denied

0 /var/log/samba

du: cannot read directory ‘/var/log/ppp’: Permission denied

0 /var/log/ppp

0 /var/log/ntpstats

du: cannot read directory ‘/var/log/audit’: Permission denied

0 /var/log/audit

du: cannot read directory ‘/var/log/mariadb’: Permission denied

0 /var/log/mariadb

0 /var/log/chrony

0 /var/log/glusterfs

172K /var/log/cups

du: cannot read directory ‘/var/log/speech-dispatcher’: Permission denied

0 /var/log/speech-dispatcher

du: cannot read directory ‘/var/log/gdm’: Permission denied

4.0K /var/log/gdm

4.1M /var/log/sa

0 /var/log/qemu-ga

280K /var/log/tuned

940K /var/log/anaconda

0 /var/log/lightdm

24M /var/log/

[hydev@localhost ~]$ sudo du -h /var/log/

0 /var/log/sssd

0 /var/log/samba/old

0 /var/log/samba

0 /var/log/ppp

0 /var/log/ntpstats

38M /var/log/audit

36K /var/log/mariadb

0 /var/log/chrony

0 /var/log/glusterfs

172K /var/log/cups

0 /var/log/speech-dispatcher

684K /var/log/gdm

4.1M /var/log/sa

0 /var/log/qemu-ga

280K /var/log/tuned

940K /var/log/anaconda

0 /var/log/lightdm

61M /var/log/

[hydev@localhost ~]$ sudo cd /var/log/audit

[hydev@localhost ~]$ pwd

/home/hydev

[hydev@localhost ~]$ cd /var/log/audit

bash: cd: /var/log/audit: Permission denied

[hydev@localhost ~]$ sudo cd /var/log/audit

[hydev@localhost ~]$ pwd

/home/hydev

[hydev@localhost ~]$ cd /var/log/audit

bash: cd: /var/log/audit: Permission denied

[hydev@localhost ~]$ chmod -R 777 /var/log/audit

chmod: changing permissions of ‘/var/log/audit’: Operation not permitted

chmod: cannot read directory ‘/var/log/audit’: Permission denied

[hydev@localhost ~]$ sudo chmod -R 777 /var/log/audit

[hydev@localhost ~]$ cd /var/log/audit

[hydev@localhost audit]$ du -h *

5.1M audit.log

8.1M audit.log.1

8.1M audit.log.2

8.1M audit.log.3

8.1M audit.log.4

[hydev@localhost audit]$ du -h

38M .

[hydev@localhost audit]$ cat /dev/null > audit.log.4

[hydev@localhost audit]$ du -h *

5.1M audit.log

8.1M audit.log.1

8.1M audit.log.2

8.1M audit.log.3

0 audit.log.4

[hydev@localhost audit]$ cat /dev/null > audit.log.3

[hydev@localhost audit]$ du -h *

5.1M audit.log

8.1M audit.log.1

8.1M audit.log.2

0 audit.log.3

0 audit.log.4

[hydev@localhost audit]$ cat /dev/null > audit.log.2

[hydev@localhost audit]$ cat /dev/null > audit.log.1

[hydev@localhost audit]$ cat /dev/null > audit.log

[hydev@localhost audit]$ du -h *

0 audit.log

0 audit.log.1

0 audit.log.2

0 audit.log.3

0 audit.log.4

[hydev@localhost audit]$ 

hydev@localhost audit]$ du -h /var/log/

du: cannot read directory ‘/var/log/sssd’: Permission denied

0 /var/log/sssd

du: cannot read directory ‘/var/log/samba’: Permission denied

0 /var/log/samba

du: cannot read directory ‘/var/log/ppp’: Permission denied

0 /var/log/ppp

0 /var/log/ntpstats

8.0K /var/log/audit

du: cannot read directory ‘/var/log/mariadb’: Permission denied

0 /var/log/mariadb

0 /var/log/chrony

0 /var/log/glusterfs

172K /var/log/cups

du: cannot read directory ‘/var/log/speech-dispatcher’: Permission denied

0 /var/log/speech-dispatcher

du: cannot read directory ‘/var/log/gdm’: Permission denied

4.0K /var/log/gdm

3.9M /var/log/sa

0 /var/log/qemu-ga

280K /var/log/tuned

940K /var/log/anaconda

0 /var/log/lightdm

23M /var/log/

[hydev@localhost audit]$ sudo du -h /var/log/

0 /var/log/sssd

0 /var/log/samba/old

0 /var/log/samba

0 /var/log/ppp

0 /var/log/ntpstats

8.0K /var/log/audit

36K /var/log/mariadb

0 /var/log/chrony

0 /var/log/glusterfs

172K /var/log/cups

0 /var/log/speech-dispatcher

684K /var/log/gdm

3.9M /var/log/sa

0 /var/log/qemu-ga

280K /var/log/tuned

940K /var/log/anaconda

0 /var/log/lightdm

24M /var/log/

[hydev@localhost audit]$ sudo chmod -R 777 /var/log/sa

[hydev@localhost audit]$ du -h *

12K audit.log

0 audit.log.1

0 audit.log.2

0 audit.log.3

0 audit.log.4

[hydev@localhost audit]$ cd /var/log/sa

[hydev@localhost sa]$ du -h *

112K sa02

176K sa03

216K sa04

168K sa05

180K sa06

168K sa09

196K sa10

260K sa11

4.0K sa12

184K sa14

132K sa15

100K sa16

180K sa20

120K sa21

208K sa22

188K sa23

216K sa26

196K sa27

192K sa28

152K sa29

20K sa30

140K sar03

216K sar11

176K sar26

[hydev@localhost sa]$ pwd

/var/log/sa

[hydev@localhost sa]$ sudo chmod -R 777 /var/log/cups

[hydev@localhost sa]$ cd /var/log/cups

[hydev@localhost cups]$ du -h *

0 access_log

80K access_log-20170314

56K access_log-20170322

8.0K access_log-20191123

4.0K access_log-20191203

0 error_log

4.0K error_log-20170314

4.0K error_log-20170322

4.0K error_log-20191123

4.0K error_log-20210721

0 page_log

4.0K page_log-20191123

[hydev@localhost cups]$ cat /dev/null > access_log-20170314

[hydev@localhost cups]$ du -h *

0 access_log

0 access_log-20170314

56K access_log-20170322

8.0K access_log-20191123

4.0K access_log-20191203

0 error_log

4.0K error_log-20170314

4.0K error_log-20170322

4.0K error_log-20191123

4.0K error_log-20210721

0 page_log

4.0K page_log-20191123

[hydev@localhost cups]$ cat /dev/null > access_log-20170322

[hydev@localhost cups]$ cat /dev/null > access_log-20191123

[hydev@localhost cups]$ cat /dev/null > access_log-20191203

[hydev@localhost cups]$ cat /dev/null > error_log-20170314

[hydev@localhost cups]$ cat /dev/null > error_log-20170322

[hydev@localhost cups]$ cat /dev/null > error_log-20191123

[hydev@localhost cups]$ cat /dev/null > error_log-20210721

[hydev@localhost cups]$ cat /dev/null > page_log-20191123

[hydev@localhost cups]$ du -h *

0 access_log

0 access_log-20170314

0 access_log-20170322

0 access_log-20191123

0 access_log-20191203

0 error_log

0 error_log-20170314

0 error_log-20170322

0 error_log-20191123

0 error_log-20210721

0 page_log

0 page_log-20191123

[hydev@localhost cups]$