Checking if a function's result is above a certain number always false

Question

I`m try to check my ttl value with alias in .bashrc file by function like this:

# awk ttl
function awkTTL() {

ping 8.8.8.8 -c 1 | grep 'ttl' | awk -F '[ :=]' '{print $9}'

}

# check connection
function checkOnline() {

awkTTL

if [[ awkTTL -ge 2 ]]; then
    echo "online"
else
    echo "offline"
fi
}

alias -g ww=checkOnline

and always i got answer like this

107 # current ttl value
offline # echo from function

Answer 1

First, all the below assumes that your ping command has output formatted such that your original awk works as-is. If that assumption isn't true (and not all ping commands do work with that, f/e, one I'm trying to test with puts the value in $10 instead of $9), the below examples (except for the pure-bash one that doesn't use awk at all) aren't expected to work either.

---

A better implementation of the checkOnline function could look like:

# caution: this awk code doesn't work for all versions of ping
awkTTL() { ping 8.8.8.8 -c 1 | awk -F '[ :=]' '/ttl/ {print $9}'; }

checkOnline() {
  if [[ $(awkTTL) -ge 2 ]]; then
    echo "online"
  else
    echo "offline"
  fi
}

Using a command substitution (the $( ... ) syntax) means we're putting the output of running awkTTL into the [[ argument list, instead of the string 'awkTTL'. Because the string 'awkTTL' isn't a number, attempts to compare it against a number fail.

---

By the way, you could also just do the whole thing in awk, and not need bash to read or compare awk's output at all:

# note that this still assumes ttl is in $9, per the OP's original code
checkOnline() {
  awk -F '[ :=]' '
    BEGIN                          { ttl=0 }
    /ttl/ && $9 ~ /^[[:digit:]]+$/ { ttl=$9 }
    END   { if (ttl >= 2) { print "online" } else { print "offline" } }
  ' < <(ping 8.8.8.8 -c1)
}

---

...or, to do the whole thing in bash, without any need for awk:

checkOnline() {
  local line highestTTL=0
  while IFS= read -r line; do
    if [[ $line =~ [[:space:]]ttl=([[:digit:]]+)([[:space:]]|$) ]]; then
      highestTTL=${BASH_REMATCH[1]}
    fi
  done < <(ping 8.8.8.8 -c 1)
  if (( highestTTL >= 2 )); then
    echo "online"
  else
    echo "offline"
  fi
}

Answer 2

awkTTL in this case is echoing directly to the console, so you won't be able to easily capture the value for a test in your if statement. I would recommend instead having the awkTTL function return the value, which could be captured or echoed:

function awkTTL() {
  ping 8.8.8.8 -c 1 | grep 'ttl' | awk -F '[ :=]' '{print $9}'
}

function checkOnline() {
  ttl = $(awkTTL) # capture value from the function
  echo $ttl
  if [[ $ttl -ge 2 ]]; then
    echo 'online'
  else
    echo 'offline'
  fi
}

I have no idea where your "smaller" string is coming from. Only guess here is that is from a previous version of the script that is being executed instead of the one you posted.