Grep a word

Shell Programming and Scripting
1

Hi All,

I am new to scripting and wondering why grep is resulting in incorrect result when i am trying to find a word from a piped result.:mad:

]# fdisk -l

Disk /dev/sda: 6442 MB, 6442450944 bytes
255 heads, 63 sectors/track, 783 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1          13      104391   83  Linux
/dev/sda2              14         783     6185025   8e  Linux LVM

Disk /dev/sdb: 32.2 GB, 32212254720 bytes
255 heads, 63 sectors/track, 3916 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1   *           1        3916    31455238+  83  Linux

Disk /dev/sdc: 268 MB, 268435456 bytes
64 heads, 32 sectors/track, 256 cylinders
Units = cylinders of 2048 * 512 = 1048576 bytes

Disk /dev/sdc doesn't contain a valid partition table

Disk /dev/sdd: 268 MB, 268435456 bytes
64 heads, 32 sectors/track, 256 cylinders
Units = cylinders of 2048 * 512 = 1048576 bytes

Disk /dev/sdd doesn't contain a valid partition table
]#

and ran be below command to fetch the line which contain "sdb"

[root@LRC109-RNC2-3GOAM-0 ~]# fdisk -l |  grep sdb
Disk /dev/sdc doesn't contain a valid partition table
Disk /dev/sdd doesn't contain a valid partition table
Disk /dev/sdb: 32.2 GB, 32212254720 bytes
/dev/sdb1   *           1        3916    31455238+  83  Linux
[root@LRC109-RNC2-3GOAM-0 ~]#

I need only the line with "sdb" but grep is throwing a different result.

I need to include similar kind of stuff in a shell script to deal with some devices information
Please help me in this regards.

2

Probably program is writing some lines to STDERR.
Try:

fdisk -l 2>&1 |  grep sdb