how to solve ${path:1:4} problem

nagendrar · 05-05-2010, 03:19 AM

I have following in mu script.

Code:

path=/test/test1
echo ${path:1:4}

It gives "test" as output in Linux. But fails in solaris and gives error "bad substitution"

Please help me

ThanQ,
Nagendra.

druuna · 05-05-2010, 03:29 AM

Hi,

Which bash (ksh??) version are you using?

I'm not sure if parameter expansion is supported by the version of bash/ksh that comes with solaris. Check the manpage on the sun box.

If it is not supported you need to work around it using other tools available (sed/cut/awk/..).

Hope this helps.

jlliagre · 05-05-2010, 06:27 AM

This syntax is unsupported by ksh88 but works with ksh93 (might be available as dtksh on Solaris) and bash.

nagendrar · 05-07-2010, 03:23 AM

I write one function to solve this problem

Code:

cutstring(){
        if [ $2 -lt 0 ]
        then
                echo $1
                return
        fi
        if [ $3 -eq 0 ]
        then
                return
        elif [ $3 -lt 0 ]
        then
                echo "$3: substring expression < 0"
                return
        fi

        count=0
        numchar=1
        char=`expr $2 + 1`
        while :
        do
                if [ $count -eq "$2" ]
                then
                        a=`echo $1 | cut -b$char`
                        b=``$b``$a``
                        if [ $numchar-eq $3 ]
                        then
                                echo $b
                                break
                        else
                                char=`expr $char + 1`
                                numchar=`expr $numchar + 1`
                        fi
                else
                        count=`expr $count + 1`
                fi
       done
}

str=`cutstring "abcdef" 1 4`
echo $str


output of this : bcde

ThanQ,
Nagendra

jlliagre · 05-07-2010, 03:48 AM

It certainly can be optimized/simplified:

Code:

echo ${path:1:4}

can be converted to this which will work with all shells and Unix releases:

Code:

echo "$path" | cut -c2-5