我知道如何迭代字母表：
for c in {a..z}; do ...; done
但我无法弄清楚如何遍历所有ASCII字符.有谁知道怎么样？
解决方法
你可以做的是从0迭代到127然后将十进制值转换为它的ASCII值(或返回).
# POSIX
# chr() - converts decimal value to its ASCII character representation
# ord() - converts ASCII character to its decimal value
chr() {
[ ${1} -lt 256 ] || return 1
printf \\$(printf '%03o' $1)
}
# Another version doing the octal conversion with arithmetic
# faster as it avoids a subshell
chr () {
[ ${1} -lt 256 ] || return 1
printf \\$(($1/64*100+$1%64/8*10+$1%8))
}
# Another version using a temporary variable to avoid subshell.
# This one requires bash 3.1.
chr() {
local tmp
[ ${1} -lt 256 ] || return 1
printf -v tmp '%03o' "$1"
printf \\"$tmp"
}
ord() {
LC_CTYPE=C printf '%d' "'$1"
}
# hex() - converts ASCII character to a hexadecimal value
# unhex() - converts a hexadecimal value to an ASCII character
hex() {
LC_CTYPE=C printf '%x' "'$1"
}
unhex() {
printf \\x"$1"
}
# examples:
chr $(ord A) # -> A
ord $(chr 65) # -> 65
