Hi I wonder if you can help me to calculate the time difference between to times. Here is my file: 11:56:34 354940 5240832 453754 11:58:16 354788 5240832 453753 I need to subtract the last time field from the 1st & output to another file called time_taken.txt Thanks

Here is some code to work with.  Just echo and redirect what you want to time_taken.txt. I do not know the specifics of your input file.  This code takes the LAST two lines found in the input file that start with a colon-delimited time field to use as the from/to times.  If the ending time is earlier than the starting time, assumption is made that a single midnight has been traversed. #!/bin/ksh typeset -Z2 h1 m1 s1 typeset -Z2 h2 m2 s2 typeset -Z2 hh mm ss grep '^..:..:.. ' file.in | while read time remainder do h1=$h2 m1=$m2 s1=$s2 h2=$(expr "$time" : "\(..\):..:..") m2=$(expr "$time" : "..:\(..\):..") s2=$(expr "$time" : "..:..:\(..\)") done echo "from=$h1:$m1:$s1  to=$h2:$m2:$s2" seconds=$(echo "$h2*3600+$m2*60+$s2-($h1*3600+$m1*60+$s1)" | bc) if [ "$seconds" -lt 0 ] ; then    ((seconds=seconds+86400)) fi hh=$(expr $seconds / 3600) mm=$(expr \( $seconds - $hh \* 3600 \) / 60) ss=$(expr $seconds - $hh \* 3600 - $mm \* 60) echo "elapsed: $hh:$mm:$ss ($seconds seconds)" from=11:56:34  to=11:58:16 elapsed: 00:01:42 (102 seconds)

Thanks For your Help-Works great!

Hi Dave I have 1 problem with the script If I have more than 2 lines for the date I get an error - I need to calculate the 1st & last. eg: 21:20:46 102349 Audit Number Commencing 21:44:11 DAYEND Completed Check Logfiles 21:51:22 DAYEND Completed Check Logfiles 21:52:10 DAYEND Completed Check Logfiles 21:52:52 DAYEND Completed Check Logfiles 21:53:36 DAYEND Completed Check Logfiles I need to calculate the difference between 21:53:36 to 21:20:46 thanks for your help Hamim

OK, this script will process the first and last lines: #!/bin/ksh typeset -Z2 h1 m1 s1 typeset -Z2 h2 m2 s2 typeset -Z2 hh mm ss grep '^..:..:.. ' file.in | while read time remainder do h2=$(expr "$time" : "\(..\):..:..") m2=$(expr "$time" : "..:\(..\):..") s2=$(expr "$time" : "..:..:\(..\)") if [ ! "$h1" ] ; then    h1=$h2    m1=$m2    s1=$s2 fi done echo "from=$h1:$m1:$s1 to=$h2:$m2:$s2" seconds=$(echo "$h2*3600+$m2*60+$s2-($h1*3600+$m1*60+$s1)" | bc) if [ "$seconds" -lt 0 ] ; then    ((seconds=seconds+86400)) fi hh=$(expr $seconds / 3600) mm=$(expr \( $seconds - $hh \* 3600 \) / 60) ss=$(expr $seconds - $hh \* 3600 - $mm \* 60) echo "elapsed: $hh:$mm:$ss ($seconds seconds)" from=21:20:46 to=21:53:36 elapsed: 00:32:50 (1970 seconds)

Thanks Dave - I have another problem where my script has to cd into each /home directory execute & cd into the next I have a problem where it cannot exit out of the first & cd to the next Any idead - Your help is very much appreciated Thanks Hamim