I am trying to validate multiple inputs separated by spaces(two disk names in the below case) with a shell script. But, I am un-successful in doing so. Can someone help me?
read DISK
if [ "${1}" = "" ] || [ "${2}" = "" ]
then
printf "The Disk pairs cannot be left blank. Exiting script!!!"
exit 1
else
TMP=$DISK
printf "The disks entered are $TMP"
fi
For ksh93, you can use
read -A disks
if [[ ${#disks[#]} -ne 2 ]]; then
print -u2 "You need to enter 2 disks"
exit 1
else
print "You entered: ${disks[*]}"
fi
For ksh88, use the positional parameters
read disks
set -- $disks
if [[ $# -ne 2 ]]; then
print -u2 "You need to enter 2 disks"
exit 1
else
print "You entered: $disks"
fi
The variables ${1} and ${2} are the commandline parameters and are unrelated to the last read command. There are different ways to use the DISK variable.
Once you have the DISK variable read, I would have chosen for a solution like
echo "${DISK}" | while read disk1 disk2 otherfields; do
echo "disk1=${disk1}, disk2=${disk2}"
done
# or better
disk1="${DISK% *}"; echo "${disk1}"
disk2="${DISK#* }"; echo "${disk2}"
# or worse
disk1=$(echo "${DISK}" | cut -d" " -f1)
disk2=$(echo "${DISK}" | cut -d" " -f2)
When you already know you want to split the fields, you can change your first read command. Replace read DISK with
read disk1 disk2 remaining_input
Related
When I choose Option 3 after opening the file it just terminates.
I was trying to use if else function inside section 3 where it ask for new values if there is none stored so that instead of terminating it will ask for values but cant seem to work it out.
#!/bin/bash
while : #This program demonstrate 4 option below
do
clear
echo "Main Menu"
echo "Select any option of your choice"
echo "[1] Show Todays date/time,Files in current directory,home
directory,user id "
echo "[2] Enter a range "
echo "[3] Highest and lowest of the eight random numbers "
echo "[4] Exit/Stop "
echo "==========="
echo -n "Menu choice [1-4]: "
read -r yourch #Choose option out of 4
case $yourch in
1) echo "Today is";date;
echo "Your home directory is:";home;
echo "Your path is :";PWD;
echo "Current Shell";uname;
echo "Your Student ID $USER ID ";
echo "Press a key...";read -r;;
2) echo "Lower value" #Enter the lower value
read -r s1
echo "Higher value" #Enter the higher value
read -r s2
dif=$((s2-s1))
if [ $dif -ne 100 ]
then
echo "Range should be 100"
else #if the differnce is 100 then programe run otherwise terminates
in=$( ("$s2" - "$s1")) #formula for the range
echo "8 random numbers between $s1 and $s2 are :-"
for i in $(seq 1 8)
do
t=$( ($RANDOM % "$in"))
n=$( ("$t" + "$s1"))
echo "$n" #Here we get the random numbers
done
fi
echo "Press a key..."; read -r;;
3) diff=$((s2 - s1)) #Depicts Highest and lowest numbers of the randoms
RANDOM=$$
min=9999
max=-1
for i in $(seq 8)
do
R=$((((RANDOM%diff))+s1))
if [[ "$R" -gt "$max" ]]
then
max=$R
fi
if [[ "$R" -lt "$min" ]]
then
min=$R
fi
done
echo "Biggest number and smallest numbers are $max and $min" #Prints the highest and lowest numbers
echo "press a key...";read -r;;
4)echo " THANK YOU VERY MUCH $ Good Bye"
exit 0;; #Exit command
*)echo "Opps!!! Please select choice 1,2,3,4";
echo "press a key...";read -r;;
esac
done
I would like for it to ask for new values if there is no previous data stored.
I checked your script, to see the problem. It terminates with a division by zero, because s1 and s2 initially are not set. To resolve this, you can use code like
if [ -z "${s1}" ] ;then
read -p "s1 is empty, please enter a number " s1
fi
if [ -z "${s2}" ] ;then
read -p "s2 is empty, please enter a number " s2
fi
-z "..." is true, if the string is empty. The shell doesn't distinguish data types and because I use the doublequotes it is safe to check for an empty string because if s1 is not set, "$s1" results in an empty string.
Btw. "$s1" is logically equivalent to "${s1}", but it is safer to use the curly braces, because there are no ambiguities this way where the variable ends. For example consider the lines:
year=90
echo "I like the music of the $years"
#
echo "I like the music of the ${year}s"
The first echo outputs "I like the music of the" unless variable "years" was set before, while the second outputs "I like the music of the 90s". Without curly braces this would be a bit more inconvenient. Without curly braces sometimes you might run in such ambiguities, without recognizing it easily.
The problem I have is with echo cannot echo e.g: "$prefix_$suffix". This is a assignment for a class in school if that changes things.
I've tried e.g "$prefix _$suffix" but that creates a space between the prefix and suffix
#!bin/bash
read -p "Username prefix: " prefix
read -p "Amount of users: " amount
read -p "Name of file to store, include extension (e.g test.txt): " filename
touch "$filename"
new="$amount"
suffix=0
state=true
while [ state=true ] ; do
#in this function i reverse the user input amount of users so it appears as user 1,2,3 (and so on) in the first line of the text file that is also user input.
if [ "$new" -ge 1 ] ; then
newpass="$(gpg --gen-random --armor 1 12)"
#reversing process, making the suffix start at 1 so user 1 gets assigned suffix 1 for the username and i decrease the "new" variable that gets set to "$amount" so the while loop isn't indefinite
new=`expr "$new" - 1`
suffix=`expr "$suffix" + 1`
echo -n "$prefix" >> "$filename"
echo -n "_$suffix" >> "$filename"
echo -n " " >> "$filename"
echo "$newpass" >> "$filename"
echo -e >> "$filename"
elif [ "$new" -eq 0 ] ; then
break
fi
done
a run of this bash results in 5 lines e.g:
re_1 UlrZW3jB5L9zt6Nf
and so on, depending how many users you choose at the input
however the next task is to create users with the username, in this example re_1 with the password: UlrZW3jB5L9zt6Nf. This is where the clunky echo stuff I've done doesn't work. I tried doing useradd -u "$prefix_$suffix" and "$prefix $suffix" , none of these work since "$prefix$suffix" is treated as one call instead of two and the "$prefix _$suffix" adds one space in between the prefix and suffix which is not acceptable.
Even if this looks very introverted to you, hence i added comments to make it understandable, help is very appreciated.
Feel free to ask question if you do not understand and want to help!
This will do what you want:
echo "${prefix}_${suffix}"
So I have a file called "nouns" that looks like this:
English word:matching Spanish word
Englsih word:matching Spanish word
..etc etc
I need to make a program that list all the English words with an option to quit. The program displays the English words and ask the user for the word he wants translated and he can also type "quit" to exit.
This is what I have so far that shows me the list in English
select english in $(cut -d: -f1 nouns)
do
if [ "$english" = 'quit' ]
then
exit 0
fi
done
I know that I need to run a command that pulls up the second column (-f2) by searching for the corresponding English word like this
result=$(grep -w $english nouns|cut -d: -f2)
My end result should just out put the corresponding Spanish word. I am just not sure how to get all the parts to fit together. I know its based in a type of "if" format (I think) but do I start a separate if statement for the grep line?
Thanks
You need a loop in which you ask for input from user. The rest is putting things together with the correct control flow. See my code below:
while :
do
read -p "Enter word (or quit): " input
if [ "$input" = "quit" ]; then
echo "exiting ..."
break
else
echo "searching..."
result=$(grep $input nouns | cut -d ':' -f 2)
if [[ $result ]]; then
echo "$result"
else
echo "not found"
fi
fi
done
dfile=./dict
declare -A dict
while IFS=: read -r en es; do
dict[$en]=$es
done < "$dfile"
PS3="Select word>"
select ans in "${!dict[#]}" "quit program"; do
case "$REPLY" in
[0-9]*) w=$ans;;
*) w=$REPLY;;
esac
case "$w" in
quit*) exit 0;;
*) echo "${dict[$w]}" ;;
esac
done
You want to run this in a constant while loop, only breaking the loop if the user enters "quit." Get the input from the user using read to put it in a variable. As for the searching, this can be done pretty easily with awk (which is designed to work with delimited files like this) or grep.
#!/bin/sh
while true; do
read -p "Enter english word: " word
if [ "$word" = "quit" ]; then
break
fi
# Take your pick, either of these will work:
# awk -F: -v "w=$word" '{if($1==w){print $2; exit}}' nouns
grep -Pom1 "(?<=^$word:).*" nouns
done
I am creating a simple phonebook using unix shell scripts. I have gotten all of my functions to work except the removal of a contact after it has been created. I have tried combining grep and sed in order to accomplish this, but cannot seem to get over the hump. The removal shell i've tried is as follows.
#!/bin/sh
#removeContact.sh
echo “Remove Submenu”
echo “Please input First Name:”
read nameFirst
echo “Please input Last Name:”
read nameLast
x=$(grep -e “$nameFirst” -e “$nameLast” ContactList)
echo $x
sed '/'$x'/ d' ContactList;
echo “$nameFirst $nameLast is removed from your contacts”
exit 0
I'm not sure if I am declaring x incorrectly, or if my syntax is wrong when sed is used.
Any help would be greatly appreciated. Thank you.
#!/bin/bash
ContactList="contacts.txt"
export ContactList
exit=0
while [ $exit -ne 1 ]
do
echo "Main Menu"
echo "(a) Add a Contact"
echo "(r) Remove a Contact"
echo "(s) Search a Contact"
echo "(d) Display All Contact’s Information"
echo "(e) Exit"
echo "Your Choice?"
read choice
if [ "$choice" = "a" ]
then
./addContact.sh
elif [ "$choice" = "r" ]
then
./removeContact.sh
elif [ "$choice" = "s" ]
then
./searchContact.sh
elif [ "$choice" = "d" ]
then
./displayContact.sh
elif [ "$choice" = "e" ]
then
exit=1
else
echo "Error"
sleep 2
fi
done
exit 0
#!/bin/sh
#addContact.sh
ContactList="contacts.txt"
echo “Please input First Name:”
read nameFirst
echo “Please input Last Name:”
read nameLast
echo “Please input Phone Number:”
read number
echo “Please Input Address”
read address
echo “Please input Email:”
read email
echo $nameFirst:$nameLast:$number:$address:$email>> ContactList;
echo "A new contact is added to your book."
exit 0
sed '/'$x'/ d' ContactList
won't remove anything from the file ContactList, it will simply output the changes to standard output.
If you want to edit the file in-place, you'll need the -i flag (easy) or to make a temporary file which is then copied back over ContactList (not so easy, but needed if your sed has no in-place editing option).
In addition, since ContactList is a shell variable referencing the real file contacts.txt, you'll need to use $ContactList.
And, as a final note, since you're using the full line content to do deletion, the presence of an address like 1/15 Station St is going to royally screw up your sed command by virtue of the fact it contains the / character.
I would suggest using awk rather than sed for this task since it's much better suited to field-based data. With the record layout:
$nameFirst:$nameLast:$number:$address:$email
you could remove an entry with something like (including my patented paranoid perfect protection policy):
cp contacts.txt contacts.txt.$(date +%Y.%m.%d.%H.%M.%S_$$)
awk <contacts.txt >tmp.$$ -F: "-vF=$nameFirst" "-vL=$nameLast" '
F != $1 || L != $2 {print}'
mv tmp.$$ contacts.txt
This is just a simple problem but I don't understand why I got an error here. This is just a for loop inside an if statement.
This is my code:
#!/bin/bash
if (!( -f $argv[1])) then
echo "Argv must be text file";
else if ($#argv != 1) then
echo "Max argument is 1";
else if (-f $argv[1]) then
for i in `cut -d ',' -f2 $argv[1]`
do
ping -c 3 $i;
echo "finish pinging host $i"
done
fi
Error is in line 16, which is the line after fi, that is a blank line .....
Can someone please explain why i have this error ????
many, many errors.
If I try to stay close to your example code:
#!/bin/sh
if [ ! -f "${1}" ]
then
echo "Argv must be text file";
else if [ "${#}" -ne 1 ]
then
echo "Max argument is 1";
else if [ -f "${1}" ]
then
for i in $(cat "${1}" | cut -d',' -f2 )
do
ping -c 3 "${i}";
echo "finish pinging host ${i}"
done
fi
fi
fi
another way, exiting each time the condition is not met :
#!/bin/sh
[ "${#}" -ne 1 ] && { echo "There should be 1 (and only 1) argument" ; exit 1 ; }
[ ! -f "${1}" ] && { echo "Argv must be a file." ; exit 1 ; }
[ -f "${1}" ] && {
for i in $(cat "${1}" | cut -d',' -f2 )
do
ping -c 3 "${i}";
echo "finish pinging host ${i}"
done
}
#!/usr/local/bin/bash -x
if [ ! -f "${1}" ]
then
echo "Argument must be a text file."
else
while-loop-script "${1}"
fi
I have broken this up, because I personally consider it extremely bad form to nest one function inside another; or truthfully to even have more than one function in the same file. I don't care about file size, either; I've got several scripts which are 300-500 bytes long. I'm learning FORTH; fractalism in that sense is a virtue.
# while-loop-script
while read line
do
IFS="#"
ping -c 3 "${line}"
IFS=" "
done < "${1}"
Don't use cat in order to feed individual file lines to a script; it will always fail, and bash will try and execute the output as a literal command. I thought that sed printing would work, and it often does, but for some reason it very often substitutes spaces for newlines, which is extremely annoying as well.
The only absolutely bulletproof method of feeding a line to a script that I know of, which will preserve all space and formatting, is to use while-read loops, rather than substituted for cat or for sed loops, as mentioned.
Something else which you will need to do, in order to be sure about preserving whitespace, is to set the internal field seperator (IFS) to something that you know your file will not contain, and then resetting it back to whitespace at the end of the loop.
For every opening if, you must have a corresponding closing fi. This is also true for else if. Better use elif instead
if test ! -f "$1"; then
echo "Argv must be text file";
elif test $# != 1; then
echo "Max argument is 1";
elif test -f "$1"; then
for i in `cut -d ',' -f2 "$1"`
do
ping -c 3 $i;
echo "finish pinging host $i"
done
fi
There's also no argv variable. If you want to access the command line arguments, you must use $1, $2, ...
Next point is $#argv, this evaluates to $# (number of command line args) and argv. This looks a lot like perl.
Furthermore, testing is done with either test ... or [ ... ], not ( ... )
And finally, you should enclose at least your command line arguments in double quotes "$1". If you don't and there is no command line argument, you have for example
test ! -f
instead of
test ! -f ""
This lets the test fail and go on to the second if, instead of echoing the proper message.