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Top Forums Shell Programming and Scripting Strange behavior from 'read' statements. (ksh - but could be same on other shells) Post 302070321 by alexop on Tuesday 4th of April 2006 04:52:17 AM
Old 04-04-2006
Strange behavior from 'read' statements. (ksh - but could be same on other shells)

I'm getting rather frustrated with an interactive script I'm writing.

The script is divided up, with section for setting variable at the top, then functions (which make up most of the script) then basically a line at the end which calls the first function- the program moves between the functions to do it's thing.

The problem I'm having is when I'm using 'read' to ask the user to 'press return to continue' or suchlike, at some points in the script this works FINE, however at other points it just continues straight through the 'read' without waiting for input or anything. Using 'read -u' had no effect, I have also replaced all these prompts with the following function;

pressreturn() {
echo
echo "Press <RETURN> to continue."
read BLANK
}

This has had no positive effect, the script still ignores the read statement some of the time!

I'm using ksh version M-11/16/88f on AIX 5.2

Thanks for your time on this, folks. I know I havn't provided too much information, I was just hoping this was a not-uncommon gotcha that a few of you might have come up against at one point or another. If anyone requires further information please shout and I'll supply whatever you need.

Regards,

Alex
 

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SCRIPT(1)						    BSD General Commands Manual 						 SCRIPT(1)

NAME
script -- make typescript of terminal session SYNOPSIS
script [-a] [-f] [-q] [-t] [file] DESCRIPTION
Script makes a typescript of everything printed on your terminal. It is useful for students who need a hardcopy record of an interactive session as proof of an assignment, as the typescript file can be printed out later with lpr(1). If the argument file is given, script saves all dialogue in file. If no file name is given, the typescript is saved in the file typescript. Options: -a Append the output to file or typescript, retaining the prior contents. -f Flush output after each write. This is nice for telecooperation: One person does `mkfifo foo; script -f foo' and another can super- vise real-time what is being done using `cat foo'. -q Be quiet. -t Output timeing data to standard error. This data contains two fields, separated by a space. The first field indicates how much time elapsed since the previous output. The second field indicates how many characters were output this time. This information can be used to replay typescripts with realistic typing and output delays. The script ends when the forked shell exits (a control-D to exit the Bourne shell (sh(1)), and exit, logout or control-d (if ignoreeof is not set) for the C-shell, csh(1)). Certain interactive commands, such as vi(1), create garbage in the typescript file. Script works best with commands that do not manipulate the screen, the results are meant to emulate a hardcopy terminal. ENVIRONMENT
The following environment variable is utilized by script: SHELL If the variable SHELL exists, the shell forked by script will be that shell. If SHELL is not set, the Bourne shell is assumed. (Most shells set this variable automatically). SEE ALSO
csh(1) (for the history mechanism), replay(1). HISTORY
The script command appeared in 3.0BSD. BUGS
Script places everything in the log file, including linefeeds and backspaces. This is not what the naive user expects. Linux July 30, 2000 Linux
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