mjhjmtu

I'm trying to pad zero to a number

a=010
printf "%04d" $a
0008

I need the "output" as "0010"
it's converting the value.

and even tried with typeset

a=010
typeset -RZ2 a
echo $a

when I use the same in my script I got the following error:

Invalid -R option

Don't put a "0" at the beginning of the number -- it treats the number in the octal base. Simply assign the decimal number.

a=10 
printf "%04d" $a 
0010 

If you are reading the numbers from somewhere else, you may consider removing the 0s at the beginning as follows:

a=0010 
b=$(echo $a | sed 's/^0*//') 
printf "%04d" $a 
0008
printf "%04d" $b 
0010 

Under POSIX shell

You can drop the left 0 character with the following:

a=00010
while [ "$a" != "$a#0" ] ;do a=$a#0;done
printf "%08d" $a
00000010

As this doesn't fork a new command session, this could be quicker than using sed.

Under bash

You can force decimal interpretation with the following syntax:

a=000010
printf "%08d" $((10#$a))
00000010

This could be useful for conversions:

a="0a"
printf "%04d" $((16#$a))
0010

a="00001010"
printf "%04d" $((2#$a))
0010

a="00012"
printf "%04d" $((8#$a))
0010

a="0020"
printf "%04d" $((5#$a))
0010

a="0013"
printf "%04d" $((7#$a))
0010

and so on...

a="zz"
printf "%04d" $((36#$a))
1295

typeset -Z4 a will work with zsh or ksh.

When interpreted as a number, In POSIX sh and printf, if there's a leading zero, it's interpreted as an octal number. So, you need to strip those 0s first:

printf '%04dn' "$a#"$a%%[!0]*""

Or you could use awk that doesn't have that issue:

awk 'BEGINprintf "%04dn", ARGV[1]' "$a"

You can accomplish that by using a different conversion specifier, for example the "f" specifier. From the printf manual:

f, F

The double argument is rounded and converted to decimal notation in
the style [-]ddd.ddd, where the number of digits after the
decimal-point character is equal to the precision specification. If
the precision is missing, it is taken as 6; if the precision is
explicitly zero, no decimal-point character appears. If a decimal
point appears, at least one digit appears before it.

But we don't really want a floating point representation of your number, so we must specify a precision of zero. This should do it:

a=010
printf "%04.0f" $a

I'm assuming you are using Linux, but this should also work with other flavours of Unix.