[root@node1 ~]# df -hT
Filesystem Type Size Used Avail Use% Mounted on
/dev/sda1 xfs 10G 10G 11M 100% /

[root@node1 ~]# du -h /| grep ‘[0-9\.]\+G’
1.3G /var/lib
5.8G /var/log/jenkins
5.8G /var/log
7.3G /var
4.0K /usr/share/locale/zh_CN.GB2312/LC_MESSAGES
4.0K /usr/share/locale/zh_CN.GB2312
1.8G /usr
10G /

compress the file with tar i my case even i dont have space to place compressed file.

[root@node1 ~]# tar -zcf jenkins_log.tar.gz /var/log/jenkins/jenkins.log
gzip: stdout: No space left on device

or

scp it to another system

[root@node1 ~]# cat /var/log/jenkins/jenkins.log |wc -l
63868959

[root@node1 ~]# echo “” > /var/log/jenkins/jenkins.log
[root@node1 ~]# du -sh /var/log/jenkins/jenkins.log
4.0K /var/log/jenkins/jenkins.log

[root@node1 ~]# df -hT
Filesystem Type Size Used Avail Use% Mounted on
/dev/sda1 xfs 10G 4.3G 5.8G 43% /