Useful Linux Commands

1.Incremental copy

rsync -avxHAX --progress / /new-disk/

The options are:

-a  : all files, with permissions, etc..
-v  : verbose, mention files
-x  : stay on one file system
-H  : preserve hard links (not included with -a)
-A  : preserve ACLs/permissions (not included with -a)
-X  : preserve extended attributes (not included with -a)

To improve the copy speed, add -W (--whole-file), to avoid calculating deltas/diffs of the files. This is the default when both the source and destination are specified as local paths, since the real benefit of rsync’s delta-transfer algorithm is reducing network usage.

Also consider adding --numeric-ids to avoid mapping uid/gid values by user/group name.

2. Format the new partition’s filesystem as type ext4

mkfs -t ext4 /dev/sdx1

3. Partition a disk

sudo fdisk /dev/sda

4. Get Directory Size

du -hs

5. Free reserved disk space

sudo tune2fs -m 0 /dev/sdb1

6. Recursively counting number of files

find DIR_NAME -type f | wc -l

7. Recursive search for text

grep -rnw '/path/to/somewhere/' -e "pattern"

• -r or -R is recursive,
• -n is line number, and
• -w stands match the whole word.
• -l (lower-case L) can be added to just give the file name of matching files.
• Along with these, --exclude or --include parameter could be used for efficient searching. Something like below:

8. sync + SSH

rsync -as -e “ssh -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null” –info=progress2 –delete-after ./work/ teng@192.168.1.224:/home/teng/work/