I have 3 scripts (I have removed the help_page function from the networkstats.sh script when I pasted here to save some space):



output = shell_exec('/bin/bash /usr/share/nginx/status/getnetworkstatsin.sh');
echo $output;



ssh -i /tmp/id_rsa1 root@centos7clone bash -s -- -I < ./networkstats.sh




read -r inbytesold outbytesold < <(awk -v dev="^$interface:" '$1 ~ dev {
              sub(/[^:]*:/,""); print $1, $9; exit }' /proc/net/dev)

sleep 1

read -r inbytesnew outbytesnew < <(awk -v dev="^$interface:" '$1 ~ dev {
              sub(/[^:]*:/,""); print $1, $9; exit }' /proc/net/dev)

kilobitsin=$(( ( ( inbytesnew - inbytesold ) * 8 ) / 1024 ))

kilobitsout=$(( ( ( outbytesnew - outbytesold ) * 8 ) / 1024 ))

show_outgoing() {
echo $kilobitsout

show_all() {
echo "kilobits in: $kilobitsin"
echo "kilobits out: $kilobitsout"

if [[ $# -eq 0 ]];
        exit 1

for arg in "$@"
        case $arg in




The problem I have is that when I execute the api3.php script from console, it is able to execute and return a value.

However when I try and execute from a webpage it fails to return anything.

I believe it is not even executing when I load it via the webpage by navigating to localhost/api3.php. Can someone help, what is the reason behind this? I have added

nginx ALL=NOPASSWD: /usr/share/nginx/status/getnetworkstatsin.sh

To my visudo section, I have tried to change permissions of all files involved to 777 (temporally) without success.

All these scripts are located inside /usr/share/nginx/status which nginx has access to.

  • networkstats.sh might not get a PATH over web requests and thus does not know where to find the binaries? – Karlo Aug 8 '14 at 11:24
  • Sounds like you need to either capture STDERR, or look at wherever STDERR gets dumped to (logs). – Patrick Aug 21 '14 at 1:04
  • Any PHP errors? You're not properly defining the variable "output" in api3.php. – redburn Aug 28 '14 at 15:38

You don't have an active console when invoking the script from php. Add the -tt switch to your ssh command.

-t Force pseudo-tty allocation. This can be used to execute arbitrary screen-based programs on a remote machine, which can be very useful, e.g. when implementing menu services. Multiple -t options force tty allocation, even if ssh has no local tty.

Source: man ssh

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