對(duì)于用戶輸入日期的合法性檢驗(yàn)，是個(gè)很重要的問(wèn)題，這個(gè)例子是簡(jiǎn)單得取得用戶輸入的日期，并轉(zhuǎn)換為相應(yīng)的格式，但不完美，原因請(qǐng)看后文。
#!/bin/sh
# normdate -- Normalizes month field in date specification
# to three letters, first letter capitalized. A helper
# function for Script #7, valid-date. Exits w/ zero if no error.
monthnoToName()
{
# Sets the variable 'month' to the appropriate value
case $1 in
1 ) month="Jan" ;; 2 ) month="Feb" ;;
3 ) month="Mar" ;; 4 ) month="Apr" ;;
5 ) month="May" ;; 6 ) month="Jun" ;;
7 ) month="Jul" ;; 8 ) month="Aug" ;;
9 ) month="Sep" ;; 10) month="Oct" ;;
11) month="Nov" ;; 12) month="Dec" ;;
* ) echo "$0: Unknown numeric month value $1" >2; exit 1
esac
return 0
}
## Begin main script
if [ $# -ne 3 ] ; then
echo "Usage: $0 month day year" >2
echo "Typical input formats are August 3 1962 and 8 3 2002" >2
exit 1
fi
if [ $3 -lt 99 ] ; then
echo "$0: expected four-digit year value." >2; exit 1
fi
if [ -z $(echo $1|sed 's/[[:digit:]]//g') ]; then
monthnoToName $1
else
# Normalize to first three letters, first upper, rest lowercase
month="$(echo $1|cut -c1|tr '[:lower:]' '[:upper:]')"
month="$month$(echo $1|cut -c2-3 | tr '[:upper:]' '[:lower:]')"
fi
echo $month $2 $3
exit 0
