linux - 将#!/bin/ksh 日期转换函数翻译成#!/bin/sh

Question

我使用这个 ksh 函数将“1-Jan-2011”格式转换为“1.1.2011”。

#!/bin/ksh

##---- function to convert 3 char month into numeric value ----------
convertDate()
{
    echo $1 | awk -F"-" '{print $1,$2,$3}' | read day mm yyyy ## split the date arg
    typeset -u mmm=`echo $mm` ## set month to uppercase
    typeset -u months=`cal $yyyy | grep "[A-Z][a-z][a-z]"` ## uppercase list of all months
    i=1 ## starting month
    for mon in $months; do ## loop thru month list
    ## if months match, set numeric month (add zero if needed); else increment month counter
    [[ "$mon" = "$mmm" ]] && typeset -xZ2 monthNum=$i || (( i += 1 ))
    done ## end loop
    echo $day.$monthNum.`echo $yyyy | cut -c3-` ## return all numeric date format ddmmyyyy
}

但是我需要通过#!/bin/sh 来使用这个函数。所以我尝试重写它...

#!/bin/sh

##---- function to convert 3 char month into numeric value ----------
convertDate()
{
    echo $1 | awk -F"-" '{print $1,$2,$3}' | read day mm yyyy ## split the date arg
    echo $mm #IT SEEMS LIKE THE PROBLEM IS IN THE PREVIOUS LINE, BECAUSE THIS VARIABLE IS EMPTY IN #!/bin/sh, BUT IF YOU CHANGE IT TO #!/bin/ksh EVERYTHING SEEM TO BE FINE, THEN FUNCTION WORKS CORRECTLY.
    mmm=`echo $mm | tr '[a-z]' '[A-Z]'`
    months=`cal $yyyy | grep "[A-Z][a-z][a-z]" | tr '[a-z]' '[A-Z]'`
    i=1 ## starting month
    for mon in $months; do ## loop thru month list
    ## if months match, set numeric month (add zero if needed); else increment month counter
    if [ "$mon" = "$mmm" ]; then
        monthNum=`printf '%02d' $i`
    else
        i=`expr $i + 1`
    fi
    done ## end loop
    echo $day.$monthNum.`echo $yyyy | cut -c3-` ## return all numeric date format ddmmyyyy
}

convertDate "20-May-2010"

但它不起作用(阅读最后一个脚本中的大写注释):(

帮助!

Answer 1

问题在于，read 命令是否由于管道而在子 shell 中运行，具体取决于 /bin/sh 是哪个 shell；您将从 bash 获得一种行为，而从传统 UNIX(例如 Solaris)/bin/sh 获得另一种行为。请改用 set。

set -- `echo $1 | awk -F"-" '{print $1,$2,$3}'`

虽然我可能会写

oIFS="$IFS"
IFS=-
set -- $1
IFS="$oIFS"