bash optional command in variable - bash

Question

i have a code:
L12(){
echo -e "/tftpboot/log/archive/L12/*/*$sn*L12*.log /tftpboot/log/diag/*$sn*L12*.log"
command="| grep -v hdd"
}
getlog(){
echo $(ls -ltr $(${1}) 2>/dev/null `${command}` | tail -1)
}
however $command does not seem to be inserting | grep -v hdd correctly
i need $command to be either empty or | grep
is there a simple solution to my issue or should i go for different approach
edit:
there may be another problem in there
i am loading a few "modules"
EVAL.sh
ev(){
case "${1}" in
*FAIL*) paint $red "FAIL";;
*PASS*) paint $green "PASS";;
*)echo;;
esac
result=${1}
}
rackinfo.sh (the "main script")
#! /bin/bash
#set -x
n=0
for src in $(ls modules/)
do
source modules/$src && ((n++))
## debugging
# source src/$src || ((n++)) || echo "there may be an issue in $src"
done
## debugging
# x=($n - $(ls | grep src | wc -l))
# echo -e "$x plugin(s) failed to laod correctly"
# echo -e "loaded $n modules"
########################################################################
command=cat
tests=("L12" "AL" "BI" "L12-3")
while read sn
do
paint $blue "$sn\t"
for test in ${tests[#]}
do
log="$(ev "$(getlog ${test})")"
if [[ -z ${log} ]]
then
paint $cyan "${test} "; paint $red "!LOG "
else
paint $cyan "${test} ";echo -ne "$log "
fi
done
echo
done <$1
the results i get are still containing "hdd" for L12()

Answer 1

Set command to cat as a default.
Also, it's best to use an array for commands with arguments, in case any of the arguments is multiple words.
There's rarely a reason to write echo $(command). That's essentially the same as just writing command.
#default command does nothing
command=(cat)
L12(){
echo -e "/tftpboot/log/archive/L12/*/*$sn*L12*.log /tftpboot/log/diag/*$sn*L12*.log"
command=(grep -v hdd)
}
getlog(){
ls -ltr $(${1}) 2>/dev/null | "${command[#]}" | tail -1)
}