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Top Forums UNIX for Beginners Questions & Answers Noob question: How to check the total number of inputs entered by user? Post 303042047 by wisecracker on Thursday 12th of December 2019 08:26:43 AM
Old 12-12-2019
Hi jejemonx...
This is what vbe was referring to assuming you are using 'bash':
Code:
Last login: Thu Dec 12 13:15:18 on ttys000
AMIGA:amiga~> bash --version
GNU bash, version 3.2.57(1)-release (x86_64-apple-darwin18)
Copyright (C) 2007 Free Software Foundation, Inc.
AMIGA:amiga~> 
AMIGA:amiga~> 
AMIGA:amiga~> help read
read: read [-ers] [-u fd] [-t timeout] [-p prompt] [-a array] [-n nchars] [-d delim] [name ...]
    One line is read from the standard input, or from file descriptor FD if the
    -u option is supplied, and the first word is assigned to the first NAME,
    the second word to the second NAME, and so on, with leftover words assigned
    to the last NAME.  Only the characters found in $IFS are recognized as word
    delimiters.  If no NAMEs are supplied, the line read is stored in the REPLY
    variable.  If the -r option is given, this signifies `raw' input, and
    backslash escaping is disabled.  The -d option causes read to continue
    until the first character of DELIM is read, rather than newline.  If the -p
    option is supplied, the string PROMPT is output without a trailing newline
    before attempting to read.  If -a is supplied, the words read are assigned
    to sequential indices of ARRAY, starting at zero.  If -e is supplied and
    the shell is interactive, readline is used to obtain the line.  If -n is
    supplied with a non-zero NCHARS argument, read returns after NCHARS
    characters have been read.  The -s option causes input coming from a
    terminal to not be echoed.
    
    The -t option causes read to time out and return failure if a complete line
    of input is not read within TIMEOUT seconds.  If the TMOUT variable is set,
    its value is the default timeout.  The return code is zero, unless end-of-file
    is encountered, read times out, or an invalid file descriptor is supplied as
    the argument to -u.
readonly: readonly [-af] [name[=value] ...] or readonly -p
    The given NAMEs are marked readonly and the values of these NAMEs may
    not be changed by subsequent assignment.  If the -f option is given,
    then functions corresponding to the NAMEs are so marked.  If no
    arguments are given, or if `-p' is given, a list of all readonly names
    is printed.  The `-a' option means to treat each NAME as
    an array variable.  An argument of `--' disables further option
    processing.
AMIGA:amiga~> _

AND, an example of how it works:
Code:
Last login: Thu Dec 12 13:15:49 on ttys000
AMIGA:amiga~> read a b c
1
AMIGA:amiga~> echo "${a} ${b} ${c}"
1  
AMIGA:amiga~> read a b c
1 2
AMIGA:amiga~> echo "${a} ${b} ${c}"
1 2 
AMIGA:amiga~> read a b c
1 2 3
AMIGA:amiga~> echo "${a} ${b} ${c}"
1 2 3
AMIGA:amiga~> _

As you can see whether you input variables 'b' and 'c' or not they have 'NULL' values so there will always be 3 variables.
You could always use 3 separate 'read's and check each one for validity and restart the loop as required if one or more is not a number...
 

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timex(1)						      General Commands Manual							  timex(1)

NAME
timex - time a command; report process data and system activity SYNOPSIS
command DESCRIPTION
reports in seconds the elapsed time, user time, and system time spent in execution of the given command. Optionally, process accounting data for command and all its children can be listed or summarized, and total system activity during the execution interval can be reported. The output of is written on the standard error. Timex returns an exit status of 1 if it is used incorrectly, if it is unable to fork, or if it could not exec command . Otherwise, timex returns the exit status of command. Options Report the total number of blocks read or written and total characters transferred by command and all its children. This option works only if the process accounting soft- ware is installed. List process accounting records for command and all its children. The suboptions and modify the data items reported. They behave as defined in acct- com(1M). The number of blocks read or written and the number of characters transferred are always reported. This option works only if the process accounting software is installed and has been invoked to create Report total system activity (not just that due to command) that occurred during the execution interval of command. All the data items listed in sar(1M) are reported. EXAMPLES
A simple example: A terminal session of arbitrary complexity can be measured by timing a sub-shell: session commands EOT WARNINGS
Process records associated with command are selected from the accounting file by inference, since process genealogy is not available. Background processes having the same user-ID, terminal-ID, and execution time window are spuriously included. SEE ALSO
sar(1M), acctcom(1M). STANDARDS CONFORMANCE
timex(1)
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