Calculate time difference between two lines

Shell Programming and Scripting
1

i grepped the time stamp in a file as given below

now i need to calculate time difference

file data:

18:29:10
22:15:50

2

Hello vivekn,

Could you please let me know if following helps you on same.

 awk -F":" 'FNR==1{split($0,a,":");sec1=a[1]*3600+a[2]*60+a[3]} FNR==2{split($0,b,":");sec2=b[1]*3600+b[2]*60+b[3];print (sec2-sec1)/3600}'  Input_file

Output will be as follows.

 3.77778

Thanks,
R. Singh

3

thanks, I need output in following format

03:46:40

4

Hello vivekn,

Could you please try following and let me know if this helps.

awk -F":" 'FNR==1{split($0,a,":");sec1=a[1]*3600+a[2]*60+a[3]} FNR==2{split($0,b,":");sec2=b[1]*3600+b[2]*60+b[3];val=sec2-sec1;ho=int(val/3600);val=val%3600;mi=sprintf("%02d",(val/60));val=val%60;;print ho":"mi":"val}'  Input_file

Output will be as follows.

3:46:40

EDIT: Adding a non-one liner form of solution too now.

awk -F":" '
FNR==1{
  split($0,a,":");
  sec1=a[1]*3600+a[2]*60+a[3]
}
FNR==2{
  split($0,b,":");
  sec2=b[1]*3600+b[2]*60+b[3];
  val=sec2-sec1;
  ho=int(val/3600);
  val=val%3600;
  mi=sprintf("%02d",(val/60));
  val=val%60;
  print ho":"mi":"val
}
'   Input_file

Thanks,
R. Singh

5

Great it worked, Thanks alot

6

Hi.

For one of a set of utilities for dealing with units date/time:

dateutils.ddiff -f "%H:%M:%S" 18:29:10 22:15:50

prodcuing:

3:46:40

On a system like:

OS, ker|rel, machine: Linux, 3.16.0-4-amd64, x86_64
Distribution        : Debian 8.9 (jessie) 
bash GNU bash 4.3.30

Some details about ddiff :

dateutils.ddiff Compute duration from DATE/TIME (the reference date/ti... (man)
Path    : /usr/bin/dateutils.ddiff
Package : dateutils
Home    : http://www.fresse.org/dateutils
Version : 0.3.1
Type    : ELF 64-bit LSB shared object, x86-64, version 1 ( ...)
Help    : probably available with -h,--help
Home    : https://github.com/hroptatyr/dateutils (doc)

Best wishes ... cheers, drl