PHP：如何获取特定VLAN的IP地址

Question

Background: A page should display SNMP data from various devices in a mgmt vlan, to loop through all IP addresses in the network. I need to know the IP address/network, the interface is on.

In Bash this works perfectly:

/sbin/ip addr show dev eth0.1100 | /usr/bin/awk  '/global/ { $2=substr($2, 1, length($2)-7); print $2 }'

But in PHP I can't find a way to get the IP address/network of the mgmt vlan. I tried:

$mgmtiface = shell_exec("/usr/bin/sudo /usr/bin/awk '$3 == 1100 {print $1}' /proc/net/vlan/config");
$mgmtnet = shell_exec("/sbin/ip addr show dev $mgmtiface | /usr/bin/awk  '/global/ { $2=substr($2, 1, length($2)-7); print $2 }' ");

But PHP doesn't like pipe in shell_exec .

How do I solve this?

Interesting, defining the interface hardcoded works fine, but as soon as I put a variable with the interface in it, it won't work:

$mgmtnet = shell_exec("/sbin/ip addr show dev eth0.1100 | /usr/bin/awk  '/global/ { $2=substr($2, 1, length($2)-7); print $2 }' ");

Answer 1

shell_exec returns the entire output, including the trailing newline. You need to trim that off before you substitute into the next command:

$mgmtiface = teim(shell_exec("/usr/bin/sudo /usr/bin/awk '$3 == 1100 {print $1}' /proc/net/vlan/config"));
$mgmtnet = trim(shell_exec("/sbin/ip addr show dev $mgmtiface | /usr/bin/awk  '/global/ { $2=substr($2, 1, length($2)-7); print $2 }' "));

If you know the command just returns one line of output, you can use exec instead of shell_exec . It returns the last line, without the newline, so you don't need to trim it.