Open and edit a file using a shell script

Shell Programming and Scripting
1

Hello Folks,
I have a file named as date.dat present at /tmp/abc location which has following data -

20161030,20161031,20161101

I need to remove this line and replace it with something like below -

$param1,$param2,$param3

Param1, Param2 and param3 stores the date based on some calculation in the same script.
Any leads will be greatly appreciated.

2

First off: what do you mean by "something like"? I am sure you look for a solution, not something like a solution , no? So, please, tell us what you need, not "something alike".

If i get you correctly you want to replace a line in a file with 3 selectable values, yes?

If so:

#! /bin/ksh

typeset chVal1="$1"
typeset chVal2="$2"
typeset chVal3="$3"
typeset fIn="/tmp/abc/date.dat"

sed '/^20161030,20161031,20161101$/ {
             s/20161030/'"$chVal1"'/
             s/20161031/'"$chVal2"'/
             s/20161101/'"$chVal3"'/
      }' "$fIn" > "$fIn".tmp

if [ $? -eq 0 ] ; then
     mv "$fIn".tmp "$fIn"
else
     print -u2 "Error editing file!
     rm -f "$fIn".tmp
     exit 1
fi

exit 0

Save this to a file script.sh , flag it executable and call it with ./script.sh "param1" "param2" "param3" .

Note that the script is a barebone solution - no effort is made for paramter checking, etc.. Add this functionality ad libitum.

I hope this helps.

bakunin