删除/etc/fstab文件中所有以#开头，后面至少跟一个空白字符的行的行首的#和空白字符

[16:36:16 root@centos8 ~]#cat -A /etc/fstab
$
#$
# /etc/fstab$
# Created by anaconda on Mon Jul 19 12:39:26 2021$
#$
# Accessible filesystems, by reference, are maintained under '/dev/disk/'.$
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info.$
#$
# After editing this file, run 'systemctl daemon-reload' to update systemd$
# units generated from this file.$
#$
UUID=a09f483f-5645-4bf5-84e6-74ff560bfcab /                       xfs     defaults        0 0$
UUID=a7cdba8a-1b4f-4cf3-ace5-809ec6b732d6 /boot                   ext4    defaults        1 2$
UUID=b1482237-a49f-4e3b-a534-bb7a1325b7d6 /date                   xfs     defaults        0 0$
UUID=30f25ee0-b7f6-47b5-978d-bc2a3d33e1d4 none                    swap    defaults        0 0$
[16:36:17 root@centos8 ~]#sed -r '/^#/s/^#[ \t]+//g' /etc/fstab |cat -A
$
#$
/etc/fstab$
Created by anaconda on Mon Jul 19 12:39:26 2021$
#$
Accessible filesystems, by reference, are maintained under '/dev/disk/'.$
See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info.$
#$
After editing this file, run 'systemctl daemon-reload' to update systemd$
units generated from this file.$
#$
UUID=a09f483f-5645-4bf5-84e6-74ff560bfcab /                       xfs     defaults        0 0$
UUID=a7cdba8a-1b4f-4cf3-ace5-809ec6b732d6 /boot                   ext4    defaults        1 2$
UUID=b1482237-a49f-4e3b-a534-bb7a1325b7d6 /date                   xfs     defaults        0 0$
UUID=30f25ee0-b7f6-47b5-978d-bc2a3d33e1d4 none                    swap    defaults        0 0$
​