Shell Programming and Scripting

START=`echo $data[$INDEX] | cut -c1-2

#!/bin/ksh
echo '*** 1st method: Using awk script... ***'
# Note that the variable names used in this awk script use the same variable
# names as the shell variables in the ksh script below.  A list of the
# variables and their use is included below for the ksh script.
#
# Note also that the echo and cat here are critical to allow awk to detect the
# EOF on the data file and display the prompt for the first round of
# interactive user input...
(echo;cat)|awk 'BEGIN{m = "Menu of options:\n"}
function mp(){printf("\n%s", m)}
{       # Throw away leading and trailing  whitespace on all input.
        sub(/^[[:space:]]*/, "")
        sub(/[[:space:]]*$/, "")
}
FNR == NR {
        # We are reading the data file here...
        if($0 == "") next # skip blank lines, sub() above made blank lines empty
        if($0 == "!")
                # Note that next non-empty data line starts a menu entry
                d1=1
        else if(d1) {
                # First line in data for menu choice mc, create menu entry
                d[++mc] = $0 "\n"
                d1=0
                m = sprintf("%s%d %s\n", m, mc,
                        match($0, /[^[:alpha:]]/) > 0 ? \
                                substr($0, 1, RSTART - 1) : $0)
        } else  # Subsequent line in data for menu choice mc
                d[mc] = d[mc] $0 "\n"
        next
}
FNR == 1 {
        # We are reading the line produced by the echo here.  Finish up the
        # menu, print the menu, and wait for the user to enter a selection:
        m = sprintf("%sEnter your choice 1 to %d (ctl-D to exit):\n", m, mc)
        mp()
        next
}
{       if($0 ~ /[^[:digit:]]/ || $0 < 1 || $0 > mc) printf("Invalid choice.\n")
        else printf("%s", d[$0])
        mp()
}' data -

sleep 1
echo '*** 2nd method: Just using ksh... ***'

# Shell variable data dictionary:
# d[x]  "d"ata for menu item x
# d1    != 0 => looking for "d"ata line #"1" for menu entry $mc
# in    current "in"put line
# m     "m"enu
# mc    "m"enu entry "c"ount
d1=0
m='Menu of options:'
while read -r in
do      if [[ "$in" == '' ]]
        then    continue        # skip empty lines in data file
        elif [[ "$in" == '!' ]]
        then    d1=1            # Next non-blank line is where we'll find the
                                # menu text and the start of the data text.
        elif [[ $d1 == 1 ]]
        then    # Gather data from 1st data line for a menu item.
                ((mc++))
                d[mc]="$(printf '%s\n' "$in")" # 1st line of data
                # Add a selection line to the menu.
                m="$(printf '%s\n%d %s' "$m" $mc "${in/%[^[:alpha:]]*/}")"
                d1=0            # no longer looking for the 1st data line
        else    # Add another line of data to the current entry.
                d[mc]="$(printf '%s\n%s' "${d[mc]}" "$in")"
        fi
done < data
m="$(printf '%s\nEnter your choice 1 to %d (ctl-D to exit): ' "$m" $mc)"
while printf '\n%s' "$m"        # Print the menu
do      if ! read -r in         # read the user's menu selection
        then    echo            # user entered ctl-d, reposition cursor & exit
                exit
        fi
        # Verify that the user's respons was not an empty line, didn't contain
        # any non-digit characters, and is a number between 1 and $mc inclusive.
        if [[ in == '' || ${in//[[:digit:]]/} != '' || in -lt 1 || in -gt mc ]]
        then    echo 'Invalid choice.'
                continue
        fi
        # We have a verified entry, print the selected data item.
        printf '%s\n' "${d[$in]}"
        # Give the user a few seconds to read the results before reprinting the
        # menu...
        sleep 2
done

!
version 12.4

service timestamps debug datetime msec
service timestamps log datetime msec

no service password-encryption

!
hostname MarcsTestbox
!

boot-start-marker
boot-end-marker
!
  logging message-counter syslog
        enable secret {FIELD DELETED] [FIELD DELETED]
!
no aaa new-model
clock timezone
        !
etc.
.
.



.

x=4
for i in {0..$x}
do echo $i
done

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