Get first character of a string SHELL

Well, you'll probably need to escape that particular value to prevent it being interpreted as a shell variable but, if you don't have access to the nifty bash substring facility, you can still use something like:

name=paxdiablofirstchar=`echo $name | cut -c1-1`

If you do have bash (it's available on most Linux distros and, even if your login shell is not bash, you should be able to run scripts with it), it's the much easier:

firstchar=${name:0:1}

For escaping the value so that it's not interpreted by the shell, you need to use:

./first \$foreignKey

and the following first script shows how to get it:

letter=`echo $1 | cut -c1-1`echo ".$letter."

This should work on any Posix compatible shell (including sh). printf is not required to be a builtin but it often is, so this may save a fork or two:

first_letter=$(printf %.1s "$1")

Note: (Possibly I should have explained this six years ago when I wrote this brief answer.) It might be tempting to write %c instead of %.1s; that produces exactly the same result except in the case where the argument "$1" is empty. printf %c "" actually produces a NUL byte, which is not a valid character in a Posix shell; different shells might treat this case differently. Some will allow NULs as an extension; others, like bash, ignore the NUL but generate an error message to tell you it has happened. The precise semantics of %.1s is "at most 1 character at the start of the argument, which means that first_letter is guaranteed to be set to the empty string if the argument is the empty string, without raising any error indication.

you can try this:

s='hello'; echo ${s:0:1}h