topic Re: restricting characters read in Operating System - HP-UX

restricting characters read

Praveen Bezawada — Thu, 10 May 2001 10:25:43 GMT

Hi
In shell scripting, can we restrict the number of character read ,using the
'read' keyword.

Re: restricting characters read

Gadura Praveen — Thu, 10 May 2001 13:10:46 GMT

Praveen,

As far as I know , read does not have any option to count the number of characters. But you can try something like this :-

read DUMMY
LENGTH=`echo ${DUMMY}|wc -m`
if [ "${LENGTH}" -gt 8 ]; then
ANSWER=`echo ${DUMMY} | cut -c 1-8`
else
ANSWER="${DUMMY}"
fi

And use the value of ANSWER to put the 8 character restriction.

Hope this helps.

Praveen

Re: restricting characters read

Carlos Fernandez Riera — Thu, 10 May 2001 13:31:57 GMT

WARNING : it is a very hard response

This output is from a menubased aplication:stty -a < /dev/pts/tb
speed 9600 baud; line = 0;
rows = 25; columns = 132
min = 1; time = 0;
intr = ^U; quit = ^\; erase = ^H; kill = ^C
eof = ^D; eol = ^@; eol2 ; swtch
stop = ^S; start = ^Q; susp ; dsusp
werase ; lnext
parenb -parodd cs8 -cstopb hupcl -cread -clocal -loblk -crts
-ignbrk brkint ignpar -parmrk -inpck -istrip -inlcr -igncr -icrnl -iuclc
-ixon -ixany ixoff -imaxbel -rtsxoff -ctsxon -ienqak
-isig -icanon -iexten -xcase -echo echoe echok -echonl -noflsh
-echoctl -echoprt -echoke -flusho -pendin
opost -olcuc -onlcr -ocrnl -onocr -onlret -ofill -ofdel -tostop

____

min=1 ; time = 0

this parameters let keep a only char from keyboard.

See man stty.

AND good luck.

Re: restricting characters read

James R. Ferguson — Thu, 10 May 2001 13:48:19 GMT

Praveen:

You can alter the IFS character and thereby redefine the words read by 'read'.

See "read" and "IFS" in 'man sh-posix'.

...JRF...