Now we will see how to read from one file and write to another. Let's write the file_04.sh script as follows:
#!/bin/bash # We are assigning descriptor 3 to in_file.txt exec 3< in_file.txt # We are assigning descriptor 4 to out_file.txt exec 4> out_file.txt # We are reading first line of input.txt read -u 3 line echo $line echo "Writing content of in_file.txt to out_file.txt" echo "Line 1 - $line " >&4 # Closing both the files exec 3<&- exec 4<&-
Save the file, give the permission to execute, and run the script as follows:
$ chmod u+x file_04.sh $ echo "Sun is at the centre of Solar System." > in_file.txt $ cat in_file.txt
This should produce the following outputs:
Sun is at the centre ...