我们可以从文件中执行grep和sed并将输出推送到变量中

Question

Trying to do grep and sed from a file and push the output into a variable

grep "^/dev/disk/by-id/scsi-*" /tmp/disks.txt | sed '{'s/=.*//'}'

Output would be like this:

/dev/disk/by-id/scsi-3644a8420420897001f2af8cc054d33bb
/dev/disk/by-id/scsi-3644a8420420897001ef50fcb0f778b86-part3
/dev/disk/by-id/scsi-3644a8420420897001ef50fcb0f778b86-part2

Error:

[/~]# grep "^/dev/disk/by-id/scsi-*" /tmp/disks.txt | sed {'s/=.*//'} >> $x
-bash: $x: ambiguous redirect

if i do this

x=`grep "^/dev/disk/by-id/scsi-*" /tmp/disks.txt | sed {'s/=.*//'}` 

or

x=$(grep "^/dev/disk/by-id/scsi-*" /tmp/disks.txt | sed {'s/=.*//'})

I get :

[root@localhost ~]# $x
-bash: /dev/disk/by-id/scsi-4644a8420420897001f2af8cc054d33bb: No such file or directory

Somehow, it is trying to resolve the disk path.

Can we push all 3 lines into a variable? Thanks!

Answer 1

The below line does push the values to the variable.

x=$(grep "^/dev/disk/by-id/scsi-*" /tmp/disks.txt | sed {'s/=.*//'})

But $x will execute each line in the x. Try echo $x to get the output of all the line stored in the variable. Although not a good idea to store multiple line in a variable as there are chances of garbling of end line characters, you can also try to store the output to a file and read it. This will save you formattign related errors.