SSH with heredoc could not modify variable

Question

I use SSH with a heredoc to control remote PC:

val=0    
ssh -p 1046 name@10.122.78.99 > result.txt 2>&1 << 'eeooff'
    echo $PATH
    echo "start"
    export vv=333
    echo $vv
    echo "end"
    val=10
eeooff
echo $val

When I check result.txt, I found echo $PATH works, but echo $vv gives nothing. Why? Is setting a variable forbidden when using SSH with a heredoc?

And $val is still 0. How to modify to 10 when using SSH with a heredoc?

I think you should ask other question and leave this question as it was. Changing the question to ask something completly different when you have a answer is not very fair, because people who have the same question as your old one was will not reach the answers to your question, edit is fair when you want to clarify your question, but no for asking something completly different. Because this I have choosed to remove my upvote. — sergiotarxz, Jan 23 '19 at 09:41
you are right. I recover the question , and bold the left question what I want to know next. — Jim Green, Jan 23 '19 at 10:46

score 1 · Answer 1 · answered Jan 23 '19 at 09:03

1

Your local shell is the one who have expand $vv, you must escape it like this \$vv.

Excuse my english.

answered Jan 23 '19 at 09:03

sergiotarxz

520
2
14

well it works, but how to avoid this except escape it like this \$vv ? – Jim Green Jan 23 '19 at 09:06
And If I define val outside, how to change it in ssh eeooff ? – Jim Green Jan 23 '19 at 09:10
I didn't understand the last question. – sergiotarxz Jan 23 '19 at 09:11
I modify the question , add val , I wanna val could be modified in ssh eeooff – Jim Green Jan 23 '19 at 09:12
I think you can not do that but you can split the ssh command in more than one taking the value of what you need outside, like this: `export a="$(ssh user@localhost \"ls\")"` – sergiotarxz Jan 23 '19 at 09:17
I need collect different ssh pcs to compare the val ? – Jim Green Jan 23 '19 at 09:19
before collect the val, I need execute many other shell scripts – Jim Green Jan 23 '19 at 09:20
I dont understand your current problem again. – sergiotarxz Jan 23 '19 at 09:22
Do you know you can put && or ; inside the ssh command to execute more than one command? I dont know if it is what you need. – sergiotarxz Jan 23 '19 at 09:24
For example, I need to collect 5 pcs program md5, and verify them whether equal – Jim Green Jan 23 '19 at 09:25
The invoker pc how to get the val which could be fetched from the remote pc？ – Jim Green Jan 23 '19 at 09:27
For example `export a[0]="$(ssh localhost \"md5sum x.patch\")", later you can use it like this echo ${a[0]} – sergiotarxz Jan 23 '19 at 09:30
@ sergiotarxz before use md5sum ,I need sudo -iu another user, and check the program exists , and cd there such as the operation, at last md5sum x.patch. – Jim Green Jan 23 '19 at 09:33
you can use -S to get the sudo password from stdin and cd like this `export a="$(ssh localhost cd Descargas \&\& ls)"` – sergiotarxz Jan 23 '19 at 09:59
@ sergiotarxz, only use sudo -iu otheruser to change to otheruser, there is no passord for stdin to login – Jim Green Jan 23 '19 at 10:37

score 0 · Answer 2 · answered Jan 23 '19 at 09:10

0

You can also:

ssh -p 1046 name@10.122.78.99 > result.txt 2>&1 << 'eeooff'

This will avoid all variable expansion. Seen here: How to avoid heredoc expanding variables?

answered Jan 23 '19 at 09:10

sergiotarxz

520
2
14

SSH with heredoc could not modify variable

2 Answers2