mirror of https://github.com/tLDP/LDP
47 lines
1.3 KiB
Bash
47 lines
1.3 KiB
Bash
#!/bin/bash
|
|
# int-or-string.sh
|
|
|
|
a=2334 # Integer.
|
|
let "a += 1"
|
|
echo "a = $a " # a = 2335
|
|
echo # Integer, still.
|
|
|
|
|
|
b=${a/23/BB} # Substitute "BB" for "23".
|
|
# This transforms $b into a string.
|
|
echo "b = $b" # b = BB35
|
|
declare -i b # Declaring it an integer doesn't help.
|
|
echo "b = $b" # b = BB35
|
|
|
|
let "b += 1" # BB35 + 1 =
|
|
echo "b = $b" # b = 1
|
|
echo
|
|
|
|
c=BB34
|
|
echo "c = $c" # c = BB34
|
|
d=${c/BB/23} # Substitute "23" for "BB".
|
|
# This makes $d an integer.
|
|
echo "d = $d" # d = 2334
|
|
let "d += 1" # 2334 + 1 =
|
|
echo "d = $d" # d = 2335
|
|
echo
|
|
|
|
# What about null variables?
|
|
e=""
|
|
echo "e = $e" # e =
|
|
let "e += 1" # Arithmetic operations allowed on a null variable?
|
|
echo "e = $e" # e = 1
|
|
echo # Null variable transformed into an integer.
|
|
|
|
# What about undeclared variables?
|
|
echo "f = $f" # f =
|
|
let "f += 1" # Arithmetic operations allowed?
|
|
echo "f = $f" # f = 1
|
|
echo # Undeclared variable transformed into an integer.
|
|
|
|
|
|
|
|
# Variables in Bash are essentially untyped.
|
|
|
|
exit 0
|