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shell中怎么判斷用戶輸入,很多新手對此不是很清楚,為了幫助大家解決這個難題,下面小編將為大家詳細(xì)講解,有這方面需求的人可以來學(xué)習(xí)下,希望你能有所收獲。
#!/bin/sh # validint -- Validates integer input, allowing negative ints too. function validint { # Validate first field. Then test against min value $2 and/or # max value $3 if they are supplied. If they are not supplied, skip these tests. number="$1"; min="$2"; max="$3" if [ -z $number ] ; then echo "You didn't enter anything. Unacceptable." >&2 ; return 1 fi if [ "${number%${number#?}}" = "-" ] ; then # is first char a '-' sign? testvalue="${number#?}" # all but first character else testvalue="$number" fi nodigits="$(echo $testvalue | sed 's/[[:digit:]]//g')" if [ ! -z $nodigits ] ; then echo "Invalid number format! Only digits, no commas, spaces, etc." >&2 return 1 fi if [ ! -z $min ] ; then if [ "$number" -lt "$min" ] ; then echo "Your value is too small: smallest acceptable value is $min" >&2 return 1 fi fi if [ ! -z $max ] ; then if [ "$number" -gt "$max" ] ; then echo "Your value is too big: largest acceptable value is $max" >&2 return 1 fi fi return 0 } if validint "$1" "$2" "$3" ; then echo "That input is a valid integer value within your constraints" fi
解析腳本:
1) number="$1"; min="$2"; max="$3" 指用戶的3個輸入;
2)nodigits="$(echo $testvalue | sed 's/[[:digit:]]//g')" 為后面測試用戶輸入的是否全為數(shù)字做準(zhǔn)備
3)if validint "$1" "$2" "$3" ; then 注意 "$1" "$2" "$3"要加引號。
4)testvalue變量是為了過濾負(fù)數(shù)后測試輸入是否全為數(shù)字的。
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