Bash-Beginners-Guide

DISKFUL=$(df -h $WEBDIR | grep -v File | awk '{print $5 }' | cut -d "%" -f1 -)
until [ $DISKFUL -ge "90" ]; do
DATE=`date +%Y%m%d`
HOUR=`date +%H`
mkdir $WEBDIR/"$DATE"
while [ $HOUR -ne "00" ]; do
DESTDIR=$WEBDIR/"$DATE"/"$HOUR"
mkdir "$DESTDIR"
mv $PICDIR/*.jpg "$DESTDIR"/
sleep 3600
HOUR=`date +%H`
done
DISKFULL=$(df -h $WEBDIR | grep -v File | awk '{ print $5 }' | cut -d "%" -f1 -)
done
TOREMOVE=$(find $WEBDIR -type d -a -mtime +30)
for i in $TOREMOVE; do
rm -rf "$i";
done
done
Note the initialization of the HOUR and DISKFULL variables and the use of options with ls and date in order
to obtain a correct listing for TOREMOVE.
9.4. I/O redirection and loops
9.4.1. Input redirection
Instead of controlling a loop by testing the result of a command or by user input, you can specify a file from
which to read input that controls the loop. In such cases, read is often the controlling command. As long as
input lines are fed into the loop, execution of the loop commands continues. As soon as all the input lines are
read the loop exits.
Since the loop construct is considered to be one command structure (such as while TEST-COMMAND; do
CONSEQUENT-COMMANDS; done), the redirection should occur after the done statement, so that it
complies with the form
command < file
This kind of redirection also works with other kinds of loops.
9.4.2. Output redirection
Bash Guide for Beginners
In the example below, output of the find command is used as input for the read command controlling a while
loop:
[carol@octarine ~/testdir] cat archiveoldstuff.sh
#!/bin/bash
# This script creates a subdirectory in the current directory, to which old
Chapter 9. Repetitive tasks 113