I am trying to verify that the format of a variable is a number and is at least 10 digits long with leading zeros, inside of an expect script.
In a bash script it would look something like this:
[[ "$var" != +([0-9]) ]] && echo "bad input" && exit
while [[ $(echo -n ${var} | wc -c) -lt 10 ]] ; do var="0${var}" ; done
For the following input:
16
I am trying to achieve the following output:
0000000016
The simplest way to check whether a variable has just digits is to use a regular expression. Expect's regular expressions are entirely up to the task:
if {![regexp {^\d+$} $var]} {
puts "bad input"
exit
}
Padding with zeroes is best done by formatting the value; if you know C's printf(), you'll recognize the format:
set var [format "%010d" $var]
format "%0*d" 10 $var; a little longer, but a little clearer (well, maybe; format strings are a bit of a black art!)
Expect is actually just an extension of TCL, so you can use any facility that TCL provides. TCL is an unusual language, but it's not hard to do what you want.
# Set a test string.
set testvar 1234567890
# Store the match (if any) in matchvar.
regexp {\d{10,}} $testvar matchvar
puts $matchvar
# Test that matchvar holds an integer.
string is integer $matchvar
The string is command is relatively new, so you might have to rely on the return value of regexp if your TCL interpreter doesn't support it.
string is it's usually best to use the -strict option: string is integer "" returns true; string is integer -strict "" returns false.regexp {\d{10,} abc1234567890def returns trueregexp {\d{10,}} abc1234567890def matchvar only stores the matched characters in matchvar, not the whole string that contains the match. It's a good-enough solution for the question as posed.