How to remove leading zeros in a string in Linux?

How to remove leading zeros in a variable or a string?

Let us consider a variable "x" which has the below value :

$ x=0010
$ echo $x
0010

1. Using typeset command of ksh:

$ typeset -LZ x
$ x=0010
$ echo $x
10

The variable x is declared using the typeset command. The -Z option of typeset will strip the leading zeros present when used along with -L option.

2. Using sed command:

$ echo $x | sed 's/^0*//'
10

The expression '^0*' will search for a sequence of 0's in the beginning and delete them.

3. Using awk :

$ echo $x | awk '{sub(/^0*/,"");}1'
10

Using the sub function of awk, explanation same as sed solution.

4. awk with printf:

$ echo $x| awk '{printf "%d\n",$0;}'
10

Using printf, use the integer format specifier %d, the leading zeros get stripped off automatically.

5. awk using int:

$ echo $x | awk '{$0=int($0)}1'
10

The int function converts a expression into a integer.

6. Perl using regex:

$ echo $x | perl -pe 's/^0*//;'
10

7. Perl with printf:

$ echo $x | perl -ne 'printf "%d\n",$_;'
10

8. Perl with int:

$ echo $x | perl -pe '$_=int;'
10