Hi there,
in this little HowTo session I’m gonna show what I’ve experienced with shell scripts (sh) and what needed to be changed, since not everyone runs bash!
Personally I haven’t read any book about it (yet), you might give me a tip which one is good?
Shell programming books on Amazon
If you KNOW you want to use bash, stop here and write perfectly fine bash code! 😉
Don’t use double brackets! [[ ]]
They are not compatible with other shells.
Instead wrap your expression in single brackets and quote the expression
if [ -z "$1" ]
instead of
if [[ -z $1 ]]
The sudo check
if [ $(id -u) != 0 ]
then
print "Please run this script as root\n"
exit 1
fi
Makes a negative root check.
Need newlines when printing something?
Normally I use echo with the -e option, which is not available.
Instead you could try
printf "Your string with\n newline"
Leave the function word out
When declaring a function just use
message() {
printf "$1\n"
}
Use #!/bin/sh as your hashbang
Make sure you do not use #!/bin/bash.
Wrap your commands right
A real POSIX shell only supports
`command`
Found more stuff? Comment it, and I’ll add it.
Cheers!