bash - Adding a zero to single digit variable -

trying add 0 before varaible if it's less 10 , create said directory. can't seem 0 add correctly. keeps resulting in making 02.1.2011, 02.2.2011 etc,etc.

i=0 in {01..31}     if $i > 10                     mkdir $path/02.0$i.2011         else                 mkdir $path/02.$i.2011     fi done 

you can replace whole lot with:

for in 0{1..9} {10..31} ;     mkdir $path/02.$i.2011 done 

while still not having start external processes (other may in loop body).

that's not important here since mkdir not 1 of things tend lot of in tight loop will important if write lot of quick , dirty code in bash.

process creation expensive when you're doing hundreds of thousands of times of scripts have done :-)

example can see in action:

pax$ in 0{7..9} {10..12}; echo $i; done 07 08 09 10 11 12 

and, if have recent-enough version of bash, honor request leading digits:

a sequence expression takes form {x..y[..incr]}, x , y either integers or single characters, , incr, optional increment, integer. when integers supplied, expression expands each number between x , y, inclusive. supplied integers may prefixed 0 force each term have same width. when either x or y begins zero, shell attempts force generated terms contain same number of digits, zero-padding necessary.

so, on debian 6 box, bash version 4.1.5:

pax$ in {07..11} ; echo $i ; done 07 08 09 10 11