UNIX for Beginners Questions & Answers

I need a script to pass the input to another script.
eg: I need a script to provide input to the sample script becuase my input value are constant.

Code:

$./sample.sh
PLease provide the comment:<input>
date:<date>
select the option:<1/2>

You are saying the answers are always the same. And you do not want to hard code them in the script because it may need to change someday.

You can use a here document:
Assume your script is named script.sh

Code:

#!/bin/bash
# example here document
./script.sh << EOF
comment, comment, comment 
`date`
1
EOF

The stuff between the EOF words is what would be typed on the keyboard.
EOF can be any combination of symbols that are not any valid UNIX or shell keyword or command.
Example -

Code:

myprog << !
stuff
!

! is not any valid keyword or command

NOTE: !! the EOF or whatever you use must match exactly on the first line and the end. Plus the last EOF has to be in column 1 - the leftmost column.
If you want to have the last EOF somewhere for easier reading use a dash (red so you see it) on line #1 before the EOF or ! or whatever.

Code:

myprog <<-EOF
stuff
       EOF

You absolutely cannot stick random "EOF" some place else in the code, other than where the true end is, when you do this. It will be treated as the end and you will get errors.

Why not redirect stdin from a file, then?

Code:

./sample.sh <my_input

with my_input being

Code:

<input>
<date>
<1/2>