Question

i have a string containing date and time as timestamp= 12-12-2012 16:45:00

I need to reformat it into timestamp= 16:45:00 12-12-2012

How to achieve this in shell script?

Note Please : variable’s value is 12-12-2012 16:45:00 and timestamp is the name of variable

#!usr/bin/expect
set timestamp "16:45:00 12-12-2012"
Now what should i do so value of timestamp will become 12-12-2012 16:45:00
script extention is .tcl example test.tcl

Answer 1

Using sed:

sed 's/\([0-9]*-[0-9]*-[0-9]*\)\([ \t]*\)\(.*\)/\3\2\1/' input

this command works on lines containing the pattern number-number-number whitespace antyhing. It simply swaps the number-number-number part \([0-9]*-[0-9]*-[0-9]*\) with the anything part \(.*\), also keeping the original whitespaces \([ \t]*\). So the replace part of sed is \3\2\1, which means the third part, white spaces, and the first part.

Same logic with tcl:

set timestamp "12-12-2012 16:45:00"
set s [regsub {([0-9]*-[0-9]*-[0-9]*)([ \t]*)(.*)} $timestamp \\3\\2\\1]
puts $s