[SOLVED] I get syntax error from awk command when querying a remote server

brh1 · 08-05-2021, 02:48 PM

Good day.

This query on a local host works just fine:

Code:

-bash-4.2$ df -P | awk '0+$5 >=40 {print}'
/dev/mapper/vg00-root              8125880 4679656   3010412      61% /
/dev/vda1                           245671  132995     95473      59% /boot

I get a syntax error from awk from remote server with this query:

Code:

-bash-4.2$ ssh -q 192.168.210.20 "df -P | awk '0+$5 >=40 {print}'"
awk: cmd. line:1: 0+ >=40 {print}
awk: cmd. line:1:    ^ syntax error

I've tried using backslashes, single and double quotes, but can't find the right answer.

Please advise.

Bjoern

wpeckham · 08-05-2021, 03:09 PM

Quote:

Originally Posted by brh1

Good day.

This query on a local host works just fine:

Code:

-bash-4.2$ df -P | awk '0+$5 >=40 {print}'
/dev/mapper/vg00-root              8125880 4679656   3010412      61% /
/dev/vda1                           245671  132995     95473      59% /boot

I get a syntax error from awk from remote server with this query:

Code:

-bash-4.2$ ssh -q 192.168.210.20 "df -P | awk '0+$5 >=40 {print}'"
awk: cmd. line:1: 0+ >=40 {print}
awk: cmd. line:1:    ^ syntax error

I've tried using backslashes, single and double quotes, but can't find the right answer.

Please advise.

Bjoern

Have you tried

Code:

ssh -q 192.168.210.20 "df -P" | awk '0+$5 >=40 {print}'

?????

brh1 · 08-05-2021, 03:54 PM

Quote:

Originally Posted by wpeckham

Have you tried

Code:

ssh -q 192.168.210.20 "df -P" | awk '0+$5 >=40 {print}'

?????

Thanks for you reply.

Your command works, but please allow me to expand on my issue. When I add a command to identify the remote host (uname -n), it prints the remote host name but then performs the 'df -P' on the local host. Note the hostnames are correct, but the numbers are all identical:

Code:

-bash-4.2$ for scf in {20..73} ; do ssh -q -o "StrictHostKeyChecking no" 192.168.210.$scf uname -n;df -P | awk '0+$5 >= 40 {print}';done
Remote-VM201scf001
/dev/mapper/vg00-root              8125880 4682900   3007168      61% /
/dev/vda1                           245671  132996     95472      59% /boot
Remote-VM202scf001
/dev/mapper/vg00-root              8125880 4682900   3007168      61% /
/dev/vda1                           245671  132996     95472      59% /boot
Remote-VM203scf001
/dev/mapper/vg00-root              8125880 4682900   3007168      61% /
/dev/vda1                           245671  132996     95472      59% /boot
Remote-VM204scf001
/dev/mapper/vg00-root              8125880 4682900   3007168      61% /
/dev/vda1                           245671  132996     95472      59% /boot
Remote-VM205scf001
/dev/mapper/vg00-root              8125880 4682900   3007168      61% /
/dev/vda1                           245671  132996     95472      59% /boot
Remote-VM206scf001
/dev/mapper/vg00-root              8125880 4682900   3007168      61% /
/dev/vda1                           245671  132996     95472      59% /boot
Remote-VM207scf001
/dev/mapper/vg00-root              8125880 4682900   3007168      61% /
/dev/vda1                           245671  132996     95472      59% /boot
Remote-VM208scf001
/dev/mapper/vg00-root              8125880 4682900   3007168      61% /
/dev/vda1                           245671  132996     95472      59% /boot

If you were to put the uname and df -h in quotes it would work if it weren't for the greater-than symbol.

Bjoern

jmgibson1981 · 08-05-2021, 04:21 PM

Code:

for scf in {20..73} ; do 
  ssh -q -o "StrictHostKeyChecking no" 192.168.210."$scf" "uname -n"
  ssh -q -o "StrictHostKeyChecking no" 192.168.210."$scf" "df -P" | awk '0+$5 >= 40 {print}';done
done

or inline true false

Code:

"uname -n && df -P" | awk '0+$5 >= 40 {print}'

The first will work for sure. I'm out of town right now so I don't have a remote to test the second one against.

The problem with formatting like this is harder to find problems imo.

Code:

for scf in {20..73} ; do ssh -q -o "StrictHostKeyChecking no" 192.168.210.$scf uname -n;df -P | awk '0+$5 >= 40 {print}';done

The reason your df isn't working is this is what you are passing with the above command. In this case you are running the df on the local machine. Hence your results.

Code:

for scf in {20..73} ; do
  ssh -q -o "StrictHostKeyChecking no" 192.168.210."$scf" uname -n
  df -P | awk '0+$5 >= 40 {print}'
done

Formatting like this is generally easier to read, again imo even if it's more lines. It also makes possible to keep in the 80 character line length which i understand is just good practices in a script.

michaelk · 08-05-2021, 04:37 PM

To elaborate on the others post

Code:

do ssh -q -o "StrictHostKeyChecking no" 192.168.210.$scf "uname -n;df -P" | awk '0+$5 >= 40 {print}';done

"uname -n;df -P" would run on the remote host but the results would be piped to awk on the localhost.

Code:

do ssh -q -o "StrictHostKeyChecking no" 192.168.210.$scf "uname -n;df -P | awk '\$5>=40 {print}'";done

One way run awk on the remote host would be to use an escape character i.e backslash to avoid variable expansion.

shruggy · 08-06-2021, 02:28 AM

May I humbly suggest df --output=pcent instead of df -P?

Code:

ssh ... 'uname -n;df --output=pcent'|awk 'NR==1||0+$0>=40'

brh1 · 08-06-2021, 11:32 AM

Quote:

Originally Posted by shruggy

May I humbly suggest df --output=pcent instead of df -P?

Code:

ssh ... 'uname -n;df --output=pcent'|awk 'NR==1||0+$0>=40'

Thanks shruggy.

Neat solution, but it only displays column 5 when I need the whole line to identify the partion:

Code:

ssh -q -o "StrictHostKeyChecking no" 192.168.210.$scf 'uname -n;df --output=pcent'|awk 'NR==1||0+$0>=40';done;echo;fi

Remote-VM201scf001
 70%
 59%

Remote-VM202scf001
 70%
 59%

Remote-VM203scf001
 70%
 59%

Remote-VM204scf001
 70%
 59%

Remote-VM205scf001
 70%
 59%

Remote-VM206scf001
 70%
 59%

Remote-VM207scf001
 70%
 59%

Remote-VM208scf001
 70%
 59%

Bjoern

brh1 · 08-06-2021, 11:46 AM

Quote:

Originally Posted by
[code

do ssh -q -o "StrictHostKeyChecking no" 192.168.210.$scf "uname -n;df -P | awk '\$5>=40 {print}'";done[/code]
One way run awk on the remote host would be to use an escape character i.e backslash to avoid variable expansion.

Thank you Michael

Your solution works, however, it also caught the 9% of the /var mount:

Code:

-bash-4.2$  for scf in {20..73} ; do echo;ssh -q -o "StrictHostKeyChecking no" 192.168.210.$scf "uname -n;df -P | awk '\$5>=40 {print}'";done
Remote-VM201scf001
Filesystem                1024-blocks    Used Available Capacity Mounted on
/dev/mapper/vg00-root         8125880 5311460   2378608      70% /
tmpfs                         8133628  508544   7625084       7% /run
/dev/vda1                      245671  133086     95382      59% /boot
/dev/mapper/vg00-var          3030800  241028   2616104       9% /var

Remote-VM202scf001
Filesystem                1024-blocks    Used Available Capacity Mounted on
/dev/mapper/vg00-root         8125880 5306844   2383224      70% /
/dev/vda1                      245671  133107     95361      59% /boot
/dev/mapper/vg00-var          3030800  236148   2620984       9% /var

Remote-VM203scf001
Filesystem                1024-blocks    Used Available Capacity Mounted on
/dev/mapper/vg00-root         8125880 5311452   2378616      70% /
/dev/vda1                      245671  133085     95383      59% /boot
/dev/mapper/vg00-var          3030800  235152   2621980       9% /var

Remote-VM204scf001
Filesystem                1024-blocks    Used Available Capacity Mounted on
/dev/mapper/vg00-root         8125880 5311468   2378600      70% /
/dev/vda1                      245671  133086     95382      59% /boot
/dev/mapper/vg00-var          3030800  235052   2622080       9% /var

When I added the '0+' it worked perfectly:

Code:

-bash-4.2$  for scf in {20..73} ; do echo;ssh -q -o "StrictHostKeyChecking no" 192.168.210.$scf "uname -n;df -P | awk '0+\$5>=40 {print}'";done

Remote-VM201scf001
/dev/mapper/vg00-root         8125880 5311460   2378608      70% /
/dev/vda1                      245671  133086     95382      59% /boot

Remote-VM202scf001
/dev/mapper/vg00-root         8125880 5306844   2383224      70% /
/dev/vda1                      245671  133107     95361      59% /boot

Remote-VM203scf001
/dev/mapper/vg00-root         8125880 5311452   2378616      70% /
/dev/vda1                      245671  133085     95383      59% /boot

Remote-VM204scf001
/dev/mapper/vg00-root         8125880 5311468   2378600      70% /
/dev/vda1                      245671  133086     95382      59% /boot

Thank you,
Bjoern

MadeInGermany · 08-06-2021, 12:46 PM

An alternative:

Code:

for scf in {20..73}
do
  echo
  ssh -q -o "StrictHostKeyChecking no" 192.168.210.$scf "/bin/bash -s" <<"_RSCRIPT_"
uname -n
df -P | awk '0+$5>=40 {print}'
_RSCRIPT_
done

brh1 · 08-06-2021, 12:53 PM

Quote:

Originally Posted by MadeInGermany

An alternative:

Code:

for scf in {20..73}
do
  echo
  ssh -q -o "StrictHostKeyChecking no" 192.168.210.$scf "/bin/bash -s" <<"_RSCRIPT_"
uname -n
df -P | awk '0+$5>=40 {print}'
_RSCRIPT_
done

Thank you, this one works as well.

Bjoern

shruggy · 08-06-2021, 01:47 PM

Quote:

Originally Posted by brh1

Neat solution, but it only displays column 5 when I need the whole line to identify the partition

Ah sorry,I somehow managed to completely misunderstand your intention. When I think of it now, of course displaying just the percentage makes little sense.