HowTo: Use tput in a shell data entry system - Part 2
Novell Cool Solutions: Feature
By Stomfi
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Posted: 8 Sep 2005 |
Learning to use Linux at Home and Work
You may remember that one of the things we needed to stop happening in the terminal was to prevent key sequences like CTRL-C having any effect.
This is done with a shell command called "trap". The command syntax is: trap action signals
In our scripts we don't want any action, but we need to put the null string "" in there which does nothing, as no given action sets the signals to their default action, not what we are trying to achieve.
If you insert this line at the start of each script after the comments, things like CTRL-C will be trapped. You can look up the man page for a lot more detail about this useful command.
trap "" 2 3 9 15
Now we come to the adjustment scripts. These scripts read and select the relevant line from the data file, display the data and allow it to be edited. The result is posted as a new record for objective evidence of the modification.
You can immediately see that we have a problem with this. How do we know how the modified entry relates to the other one, and which one does it relate to anyway?
My solution is to save the changed data in the main file with the current date, and the original in a history file. In this simple fashion, all the objective evidence of changes are saved, and it's up to the stock reconciler to follow the trail correctly.
The adjustment screen asks for a valid docket number and if it doesn't get one prints a quit message. If it does it prints the record and waits for changes or the enter key until all are done. On response from the user, the old record is saved in the history and the new record saved in the current records.
This is a picture of the first question:
Here is the adjustment record being changed:
Here is the script. The other one is the same except for the Customer field references and the output files.
#!/bin/bash
#inadjust.sh
#select and adjust an existing record by posting a new record
#If the records don't use a unique time key, which field would be selected
#in the case of text data. A time stamp could be saved as part of the
#record, but if this is to happen, it is just as easy to make the new record
#the one which is "right"and save the old data in an adjustments history file,
#replacing it in the active records with the new data.
#
#Trap signals
trap "" 2 3 9 15
#function to paint all fields onto the screen
function scrnpaint()
{
tput clear
echo ""
echo ""
echo " INWARDS GOODS ADJUSTMENT"
echo ""
echo ""
echo " Entry Date: $EDATE"
echo " Docket Number: $DOCNUM"
echo " Supplier Code: $SUPPCODE"
echo " Carrier: $CARRIER"
echo " Goods Code: $GOODSCODE"
echo " Goods Name: $GOODSNAME"
echo " Quantity: $GQUANT"
echo " Measure: $GMEAS"
echo " Received by: $RECDBY"
echo ""
echo " PRESS ENTER to ACCEPT EXISTING ENTRY"
}
#function to post history data
function dohpost()
{
echo "$ORECORD" >> $HOME/GOODS/data/inhgoods.txt
}
#function to post adjusted data
function doapost()
{
#Find and save records not matching DOCNUM
grep -v "$DOCNUM" $HOME/GOODS/data/ingoods.txt > $HOME/GOODS/data/tingoods.txt
mv -f $HOME/GOODS/data/tingoods.txt $HOME/GOODS/data/ingoods.txt
#Save adjusted record with today's date
echo "$NDATE#$DOCNUM#$SUPPCODE#$CARRIER#$GOODSCODE#$GOODSNAME#$GQUANT#$GMEAS#$RECDBY" >>
$HOME/GOODS/data/ingoods.txt
}
#Main program
#colour the screen
tput setb 6
tput clear
#Get the docket number
echo ""
echo ""
echo " INWARDS GOODS ADJUSTMENT"
echo ""
echo ""
echo " Enter Entry Docket Number for Adjustment:"
tput cup 5 44
DOCNUM=""
while [ ${#DOCNUM} -lt 1 ]
do
tput cup 5 44
read DOCNUM
done
#Get the record and fill the variables
ORECORD=`grep "$DOCNUM" $HOME/GOODS/data/ingoods.txt`
#Test for valid record
if [ "${#ORECORD}" -lt 1 ]
then
tput cup 7 10
echo "Docket Number not in Inwards Goods Record"
#Give a quit message
tput cup 8 10
echo "Press Enter to return to menu"
read menu
$HOME/GOODS/bin/inwards.sh
fi
#Set today's date for new record
NDATE=`date +%d/%m/%y`
#Assign variables from ORECORD
EDATE=`echo $ORECORD | cut -d"#" -f1`
SUPPCODE=`echo $ORECORD | cut -d"#" -f3`
CARRIER=`echo $ORECORD | cut -d"#" -f4`
GOODSCODE=`echo $ORECORD | cut -d"#" -f5`
GOODSNAME=`echo $ORECORD | cut -d"#" -f6`
GQUANT=`echo $ORECORD | cut -d"#" -f7`
GMEAS=`echo $ORECORD | cut -d"#" -f8`
RECDBY=`echo $ORECORD | cut -d"#" -f9`
#Loop around each field looking for new data or the enter key
DUNIT="ZERO"
while [ "$DUNIT" = "ZERO" ]
do
scrnpaint
tput cup 7 30
read DUNIT
if [ "${#DUNIT}" -lt 1 ]
then
SUPPCODE="$SUPPCODE"
else
if [ "$DUNIT" != "ZERO" ]
then
SUPPCODE=$DUNIT
fi
fi
done
DUNIT="ZERO"
while [ "$DUNIT" = "ZERO" ]
do
scrnpaint
tput cup 8 30
read DUNIT
if [ "${#DUNIT}" -lt 1 ]
then
CARRIER="$CARRIER"
else
if [ "$DUNIT" != "ZERO" ]
then
CARRIER=$DUNIT
fi
fi
done
DUNIT="ZERO"
while [ "$DUNIT" = "ZERO" ]
do
scrnpaint
tput cup 9 30
read DUNIT
if [ "${#DUNIT}" -lt 1 ]
then
GOODSCODE="$GOODSCODE"
else
if [ "$DUNIT" != "ZERO" ]
then
GOODSCODE=$DUNIT
fi
fi
done
DUNIT="ZERO"
while [ "$DUNIT" = "ZERO" ]
do
scrnpaint
tput cup 10 30
read DUNIT
if [ "${#DUNIT}" -lt 1 ]
then
GOODSNAME="$GOODSNAME"
else
if [ "$DUNIT" != "ZERO" ]
then
GOODSNAME=$DUNIT
fi
fi
done
DUNIT="ZERO"
while [ "$DUNIT" = "ZERO" ]
do
scrnpaint
tput cup 11 30
read DUNIT
if [ "${#DUNIT}" -lt 1 ]
then
GQUANT="$GQUANT"
else
if [ "$DUNIT" != "ZERO" ]
then
GQUANT=$DUNIT
fi
fi
done
DUNIT="ZERO"
while [ "$DUNIT" = "ZERO" ]
do
scrnpaint
tput cup 12 30
read DUNIT
if [ "${#DUNIT}" -lt 1 ]
then
GMEAS="$GMEAS"
else
if [ "$DUNIT" != "ZERO" ]
then
GMEAS=$DUNIT
fi
fi
done
DUNIT="ZERO"
while [ "$DUNIT" = "ZERO" ]
do
scrnpaint
tput cup 13 30
read DUNIT
if [ "${#DUNIT}" -lt 1 ]
then
RECDBY="$RECDBY"
else
if [ "$DUNIT" != "ZERO" ]
then
RECDBY=$DUNIT
fi
fi
done
tput cup 17 10
echo "OK to Post Entry (Y or N):"
tput cup 17 37
read OKPOST
POSTOK=`echo $OKPOST | tr a-z A-Z`
if [ "$POSTOK" = "Y" ]
then
#Save old history data
dohpost
#save new adjusted data
doapost
fi
#return to calling menu.
$HOME/GOODS/bin/inwards.sh
Now that you've learned how to use "tput", I'm going to show an even better way of doing terminal based screens in the next article.
One of the problems with the "tput" method is we can't go back up the screen to change input mistakes. With this new tool you can do all of that, and some other fancy things like we've been used to using Runtime Revolution in the GUI.
The tool is called "dialog" which processes its commands inside a shell script to give you a really professional looking out put. I sometimes think professional looking equates to boring, but you can change that if you want with this tool.
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