How to zero pad a sequence of integers in bash so that all have the same width

Question

I need to loop some values   for i in   seq  first  last  do     does something here done   For  first and  last  i need it to be of fixed length 5  So if the input is 1  i need to add zeros in front such that it becomes 00001  It loops till 99999 for example  but the length has to be 5   E g   00002  00042  00212  012312 and so forth   Any idea on how i can do that

User · Answer

This will work also   for i in  0  9  0  9  0  9  0  9  do   echo   i  done

User · Answer

In your specific case though it s probably easiest to use the -f flag to seq to get it to format the numbers as it outputs the list   For example   for i in   seq -f   05g  10 15  do   echo  i done   will produce the following output   00010 00011 00012 00013 00014 00015   More generally  bash has printf as a built-in so you can pad output with zeroes as follows     i 99   printf   05d n   i 00099   You can use the -v flag to store the output in another variable     i 99   printf -v j   05d   i   echo  j 00099   Notice that printf supports a slightly different format to seq so you need to use  05d instead of  05g

User · Answer

If you re just after padding numbers with zeros to achieve fixed length  just add the nearest multiple of 10 eg  for 2 digits  add 10 2  then remove the first 1 before displaying output   This solution works to pad format single numbers of any length  or a whole sequence of numbers using a for loop     Padding 0s zeros    Pure bash without externals eg  awk  sed  seq  head  tail etc    works with echo  no need for printf  pad 100000         5 digit fixed  for i in  0  99999   do   j pad i       echo   j    done   Tested on Mac OSX 10 6 8  Bash ver 3 2 48

User · Answer

Easier still you can just do  for i in  00001  99999   do   echo  i done

User · Answer

use printf with   05d  e g   printf   05d  1

User · Answer

Other way    zeroos  000  echo   for num in  99  105  do  echo   zeroos    num     zeroos    num  done   So simple function to convert any number would be   function leading zero         local num  1     local zeroos 00000     echo   zeroos    num     zeroos    num

User · Answer

If you want N digits  add 10 N and delete the first digit   for    num 100  num lt  105  num      do   echo   num 1 3  done   Output   01 02 03 04 05

User · Answer

One way without using external process forking is string manipulation  in a generic case it would look like this    start value CNT 1  for  whatever iterative loop  seq  cat  find     do      number of 0s is at least the amount of decimals needed  simple concatenation    TEMP  000000 CNT       for example 6 digits zero padded  get the last 6 character of the string    echo   TEMP  -6        increment  if the for loop doesn t provide the number directly    TEMP     TEMP   1    done   This works quite well on WSL as well  where forking is a really heavy operation  I had a 110000 files list  using printf   06d   NUM took over 1 minute  the solution above ran in about 1 second

User · Answer

Use awk like this   awk -v start 1 -v end 10  BEGIN for  i start  i lt  end  i    printf   05d n   i      OUTPUT   00001 00002 00003 00004 00005 00006 00007 00008 00009 00010   Update   As pure bash alternative you can do this to get same output   for i in  1  10  do    printf   05d n   i done   This way you can avoid using an external program seq which is NOT available on all the flavors of  nix

User · Answer

1   Create a sequence of numbers  seq  from 1 to 1000  and fix the width  -w   width is determined by length of ending number  in this case 4 digits for 1000     2   Also  select which numbers you want using  sed -n   in this case  we select numbers 1-100     3    echo  out each number  Numbers are stored in the variable  i   accessed using the       Pros  This code is pretty clean   Cons   seq  isn t native to all Linux systems  as I understand   for i in  seq -w 1 1000   sed -n  1 100p     do      echo  i   done

User · Answer

I pad output with more digits  zeros  than I need then use tail to only use the number of digits I am looking for  Notice that you have to use  6  in tail to get the last five digits     for i in   seq 1 10  do RESULT   echo 00000 i   tail -c 6  echo  RESULT done

User · Answer

If the end of sequence has maximal length of padding  for example  if you want 5 digits and command is  seq 1 10000    than you can use  -w  flag for seq - it adds padding itself   seq -w 1 10   produce  01 02 03 04 05 06 07 08 09 10

User · Answer

Very simple using printf   jaypal   Temp  printf   05d n  1 00001  jaypal   Temp  printf   05d n  2 00002

[bash] How to zero pad a sequence of integers in bash so that all have the same width?

Examples related to bash

Examples related to numbers

Examples related to padding