Getting error while trying to run expect script inside bash

Question

Here is my version of script that is first trying to get docker stats container wise but and then moves onto the expect part to start a tester tool to fetch stats by pressing the x key. Script is as follows:

#!/bin/bash
#!/usr/bin/expect -f

docker stats --no-stream --format "{\"container\": \"{{ .Name }}\", \"memory\": { \"raw\": \"{{ .MemUsage }}\", \"percent\": \"{{ .MemPerc }}\"}, \"cpu\": \"{{ .CPUPerc }}\"}"

#docker cp new.sh main:/app/aicore/state_tools/

docker exec main bash -c "cd aicore/state_tools; pwd;
/usr/bin/expect << 'EOF'

set timeout -1
for { set i 0 } { $i < 300000 } { incr i } {
spawn /app/aicore/state_tools/ss_tester
expect "Exit"
send -- "x\r"
expect "press"
send -- "\s03"
sleep 300
}
EOF"

The error I get is as follows: missing operand at @ in expression " @< 300000 " (parsing expression " < 300000 ") invoked from within "for { set i 0 } { < 300000 } { incr i } { spawn /app/aicore/state_tools/ss_tester expect Exit send -- xr expect press send -- s03 sleep 300 }"

Can someone please guide what am I doing wrong in the code?

Colin Macleod · Accepted Answer · 2022-03-04 14:57:14Z

1

Looks like a quoting problem. You have quoted the EOF for the here-document, which should prevent substitution on its contents, however that applies after it has been passed to docker. But before it gets to that stage it gets processed by the shell which is running your script, and that will try to substitute the $i before it even gets passed to docker. I would try putting a backslash in front of $i to prevent this, i.e. \$i .

edited Mar 4, 2022 at 14:57

answered Mar 4, 2022 at 14:52

Colin Macleod

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3 Comments

Asad Javed Over a year ago

Okay this works as I am not getting the error. Can you guide me on the keypress command. When I do send -- "x\r" it inputs xr but I want to only input x and enter.

Colin Macleod Over a year ago

Ok, I think that's another quoting issue. Try doubling the backslash to avoid this, i.e. send -- "x\\r". You probably need to do this with the other send command also.

Asad Javed Over a year ago

Aweome man..Thank you so much this really helps.

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