Question

I m attempting to write a KornShell (ksh) function that uses printf to pad a string to a certain width.

Examples:

Call

padSpaces Hello 10

Output

 Hello

I currently have:

padSpaces(){
        WIDTH=$2
        FORMAT="%-${WIDTH}.${WIDTH}s"
        printf $FORMAT $1
}

Edit: This seems to be working, in and of itself, but when I assign this in the script it seems to lose all but the first space.

TEXT=`padSpaces "TEST" 10`
TEXT="${TEXT}A"
echo ${TEXT}

Output:

TEST A

I m also open to suggestions that don t use printf. What I m really trying to get at is a way to make a fixed width file from ksh.

Answer 1

Your function works fine for me. Your assignment won t work with spaces around the equal sign. It should be:

SOME_STRING=$(padSpaces TEST 10)

I took the liberty of replacing the backticks, too.

You don t show how you are using the variable or how you obtain the output you showed. However, your problem may be that you need to quote your variables. Here s a demonstration:

$ SOME_STRING=$(padSpaces TEST 10)
$ sq= 
$ echo $sq$SOME_STRING$sq
 TEST  
$ echo "$sq$SOME_STRING$sq"
 TEST

Answer 2

Are you aware that you define a function called padSpaces, yet call one named padString? Anyway, try this:

padString() {
    WIDTH=$2
    FORMAT="%-${WIDTH}s"
    printf $FORMAT $1
}

Or, the more compact:

padString() {
    printf "%-${2}s" $1
}

The minus sign tells printf to left align (instead of the default right alignment). As the manpage states about the command printf format [ arg ... ],

The arguments arg are printed on standard output in accordance with the ANSI-C formatting rules associated with the format string format.

(I just installed ksh to test this code; it works on my machine^TM.)

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