Check dependencies on executables in a script.

bash_scripting_check_dependencies.sh

#!/bin/sh

s=0
 

if [ -x "$(which curl)" ] ; then       #This is the best option for checking...
    echo  "Utility ...... curl [ ok ]"
    else
    echo  "Utility ...... curl [fail]"
    s=1
fi
if [ -f "/bin/grep" ] && [ -x "/bin/grep" ] ; then
    echo  "grep [ ok ]"
    else
    echo  "grep [fail]"
    s=1
fi
if [ -f "/usr/bin/expr" ] && [ -x "/usr/bin/expr" ] ; then
    echo  "expr [ ok ]"
    else
    echo  "expr [fail]"
    s=1
fi
if [ -f "/bin/sed" ] && [ -x "/bin/sed" ] ; then
    echo  "sed  [ ok ]"
    else
    echo  "sed  [fail]"
    s=1
fi
if [ $s -eq 0 ]; then
    echo  "All requirements are met."
else
    echo  "Install requirements before proceeding! "
fi