Practical Example

File redirection is very common both when reading files into scripts and when outputting data from a script into a file. This example script does both of those things. It reads a .csv-formatted data file and outputs SQL INSERT statements to insert the data into a database (see Chapter 25).

The shell script uses a command line parameter to define the name of the .csv file from which to read the data. The .csv format is used to export data from spreadsheets, so you can place the database data into a spreadsheet, save the spreadsheet in .csv format, read the file, and create INSERT statements to insert the data into a MySQL database.

Here's what the script looks like:

$cat test23
#!/bin/bash
# read file and create INSERT statements for MySQL
outfile='members.sql'
IFS=','
while read lname fname address city state zip
do
   cat >> $outfile << EOF
   INSERT INTO members (lname,fname,address,city,state,zip) VALUES
('$lname', &apos...