getops still performs default actions when arguments are provided - bash

I've recently started working with the getopts command in bash. I am confused as to why my script runs the dafult action "cat ~bin/Temp/log.txt | ~bin/Scripts/report.pl" when arguments have been provided. I only want that to run if no arguments were passed to the shell script. I've used getopts:Std in perl where I was able to code somthing like:
unless ($opts{d}) {
do something...}
How would I code something like that in a shell script? Also, how would I code logic such as this:
if ($opts{c}) {
cat ~bin/Temp/mag.txt | ~bin/Scripts/report.pl -c
}
elsif ($opts{d} {
cat ~bin/Temp/mag.txt | ~bin/Scripts/report.pl -d
My code:
#!/bin/sh
while getopts cd name
do
case $name in
c)copt=1;;
d)dopt=1;;
*)echo "Invalid arg";;
esac
done
if [[ ! -z $copt ]] #Specifies what happens if the -c argument was provided
then
echo "CSV file created!"
cat "~/bin/Temp/log.txt" | ~/bin/Scripts/vpnreport/report.pl -c
fi
if [[ ! -z $dopt ]] #Specifies what happens if the -d argument was provided
then
echo "Debug report and files created"
cat ~bin/Temp/mag.txt | ~bin/Scripts/report.pl -d
fi
if [[ ! -z $name ]] #Specifies what happens if no argument was provided
then
echo "Running standard VPN report"
cat ~bin/Temp/log.txt | ~bin/Scripts/report.pl
fi
shift $(($OPTIND -1))
My Output:
[~/bin/Scripts/report]$ sh getoptstest.sh
Running standard report
[~/bin/Scripts/report]$ sh getoptstest.sh -d
Debug report and files created
Running standard report
[~/bin/Scripts/report]$
The two getopts commands are vasty different from bash to perl and I just can't seem to get the hang of the bash varient even after reading several tutorials. Any help would be greatly appreciated!

On the final run of getopts, your variable (name) will be set to "?".
#!/bin/bash
while getopts abc foo; do :; done
echo "<$foo>"
Output of the above:
$ ./mytest.sh
<?>
$ ./mytest.sh -a
<?>
Insead, use elif, which is like Perl's elsif:
if [[ ! -z $copt ]]
then
# ...
elif [[ ! -z $dopt ]]
then
# ...
else
# ...
fi
Or test if [[ -z $copt && -z $dopt ]], or so forth. Other notes:
See the official if and case documentation in the Bash manual under "Conditional Constructs".
[[ ! -z $name ]] means the same as the more-direct [[ -n $name ]].
Use #!/bin/bash instead of #!/bin/sh, or switch off of [[ in favor of [. The double square bracket (and your use thereof) is specific to bash, and rarely works with sh.

I took Jeff's answer and rewrote my script so it works now:
#!/bin/bash
while getopts cd name
do
case $name in
c)carg=1;;
d)darg=1;;
*)echo "Invalid arg";;
esac
done
#Specifies what happens if the -c argument was provided:
if [[ ! -z $carg ]]
then
if [[ -z $darg ]]
then
echo "CSV created"
cat ~bin/Temp/log.txt | ~bin/Scripts/report.pl -c
else
echo "Debug CSV created"
cat ~bin/Temp/log.txt | ~bin/Scripts/report.pl -cd
fi
fi
#Specifies what happens if the -d argurment was provided:
if [[ ! -z $darg ]]
then
echo "Debug report created"
cat ~bin/Temp/log.txt | ~bin/Scripts/report.pl -d
#Specifies what happens if no argument was provided:
else
echo "Standard report created"
cat ~bin/Temp/logs.txt | ~bin/Scripts/report.pl
fi
Thank you again for your assistance!

Related

bash execute functions based on certain word in arguments

i have the following bash script contains multiple functions
#!/usr/bin/bash
#checks if the arguments is directory and extract the domain name from it
if [[ -d "$1" ]]; then
domain=$(echo "$1" | grep -iEo '[[:alnum:]-]+\.[a-z]+')
WORKING_DIR="$1"
else
domain="$1"
echo "it is domain name"
fi
example_fun1(){
ping -c 4 $domain
}
example_fun2(){
nslookup $domain
}
for x in "$#" ;do
example_fun1 $x
example_fun2 $x
done
and run as following
./script.sh ./pathtofolder/example.com/ ./pathtofolder/test.com/
Or
./script.sh example.com test.com
and working probably BUT i need to add more feature which is check if certain word based in arguments like fun1 it will execute function example_fun1 only
desired execution
./script.sh fun1 ./pathtofolder/example.com/ ./pathtofolder/test.com/
OR
./script.sh fun1 example.com test.com
Thanks
Try the following
#!/usr/bin/bash
function=""
if [[ $( echo $1 | grep fun1 ) ]]
then
function="example_fun1"
shift
elif [[ $( echo $1 | grep fun2 ) ]]
then
function="example_fun2"
shift
fi
#checks if the arguments is directory and extract the domain name from it
example_fun1(){
ping -c 4 $domain
}
example_fun2(){
nslookup $domain
}
if [[ "$function" != "" ]]
then
for input in "$#"; do
if [[ -d "$1" ]]; then
domain=$(echo "$1" | grep -iEo '[[:alnum:]-]+\.[a-z]+')
WORKING_DIR="$1"
else
domain="$1"
echo "it is domain name"
fi
"$function"
shift
done
else
for input in "$#"; do
if [[ -d "$1" ]]; then
domain=$(echo "$1" | grep -iEo '[[:alnum:]-]+\.[a-z]+')
WORKING_DIR="$1"
else
domain="$1"
echo "it is domain name"
fi
example_fun1
example_fun2
shift
done
fi
This way you can pass fun1 and execute only fun1
Or if you don't pass any of these for example both of them will be executed
Assign the first parameter to a variable, then use that when calling the function.
func="example_$1"
shift
for x in "$#"; do
"$func" "$x"
done
And your functions need to use their parameters, not a variable that's set in the main script:
example_fun1(){
ping -c 4 "$1"
}
example_fun2(){
nslookup "$1"
}

Bash - build URL query string by parsing script command arguments

I don't use Bash very frequently but I need to work on a bit of Bash that has to make a curl request to a web service with a query string tail built from command arguments contained in the script command arguments variable $#. So if the command argument string is something like -e something -v -s somethingelse, then the query string that must be produced is e=something&v=blank&s=somethingelse.
At the moment my test script looks like this:
#!/bin/bash
set -e
echo "${#}"
query_string=""
for arg in "${#}" ; do
if [[ "${arg}" =~ "-" ]] ; then
query_string+="${arg}="
else
if [ -z "${arg}" ] ; then
query_string+="blank&"
else
query_string+="${arg}&"
fi
fi
done
echo "${query_string}" | tr -d '-'
and produces the incorrect output
e=something&v=s=somethingelse&
I'm not sure where I'm going wrong. Any suggestions would be appreciated.
How about:
#!/bin/bash
set -e
echo "${#}"
option=true
query_string=""
for arg in "${#}" ; do
if $option ; then
query_string+="${arg}="
option=false
else
if [[ "${arg}" =~ "-" ]] ; then
query_string+="blank&${arg}="
else
query_string+="${arg}&"
option=true
fi
fi
done
echo "${query_string::-1}" | tr -d '-'
Every iteration you have to check the previous arg to see if it was a switch, not a value:
#!/bin/bash
set -e
echo "${#}"
prev_arg=""
query_string=""
for arg in "${#}" ; do
if [[ $arg == -* ]] ; then
# Current arg is a switch and the previous one was also a switch
# which means the value for it is blank
if [[ $prev_arg == -* ]] ; then
query_string+="blank&"
fi
query_string+="${arg}="
else
query_string+="${arg}&"
fi
prev_arg="$arg"
done
echo "${query_string::-1}" | tr -d '-'
This produces the following output:
something -v -s somethingelse
e=something&v=blank&s=somethingelse

Unexpected if statement behaviour

I was running a small bash script, but I couldn't figure out why it was entering a if block even when condition should be false.
$ cat script.sh
#!/bin/bash
if [[ "$#"="-h" || "$#"="--help" ]]
then
echo 'Show help'
exit
fi
echo 'Do stuff'
$ ./script.sh
Show help
$ bash -x script.sh
+ [[ -n =-h ]]
+ echo 'Show help'
Show help
+ exit
$ bash -x script.sh -option
+ [[ -n -option=-h ]]
+ echo 'Show help'
Show help
+ exit
So why is $# equal to -n when I didn't pass any arguments? Also even if it is, how does -n =-h evaluate to true? When I do pass an argument -option, why is it evaluated to true, too?
Whitespace is significant. Spaces between the arguments to [[ are mandatory.
if [[ "$#" = "-h" || "$#" = "--help" ]]
Also, "$#" means "all of the command-line arguments". It would be better to just check a single argument.
if [[ "$1" = "-h" || "$1" = "--help" ]]
And for what it's worth, variable expansions in [[ don't have to be quoted. It doesn't hurt, and quoting your variables actually a good habit to develop, but if you want you can remove the quotes.
if [[ $1 = -h || $1 = --help ]]
[[ string ]] return true if string is not empty, i.e. it's a shorcut for
[[ -n string ]]
In your case, the string was =-h, that's why you see
[[ -n =-h ]]
To test for string equiality, you have to use the = (or ==) operator, that must be preceded and followed by whitespace.
[[ "$#" = "-h" ]]
Note that "$#" means all the arguments:
set -- a b c
set -x
[[ "$#" == 'a b c' ]] && echo true
gives
+ [[ a b c == \a\ \b\ \c ]]
+ echo true
true
The other answers have already explained the problems with your code. This one shows that
bashisms such as [[ ... ]] are not needed,
you can gain flexibility by using a for loop to check whether at least one of the command-line argument matches -h or --help.
Script
#!/bin/sh
show_help=0
for arg in "$#"; do
shift
case "$arg" in
"--help")
show_help=1
;;
"-h")
show_help=1
;;
*)
;;
esac
done
if [ $show_help -eq 1 ]; then
printf "Show help\n"
exit
fi
Tests
After making the script (called "foo") executable, by running
chmod u+x foo
I get the following results
$ ./foo
$ ./foo -h
Show help
$ ./foo --help
Show help
$ ./foo bar
$ ./foo bar --help
Show help
$ ./foo bar --help baz -h
Show help

How to check if arguments are legit?

I have to write a bash script which will count all the commands in a text file. Arguments to a script are -p, -n num, and a file. This means that commands like:
script.sh -n 3 -p file.txt
script -p -n 3 file.txt
and similar are all legit.
However, I have to echo an error for any commands that are not similar to this: script.sh -n -k file.txt for example.
Here is a link to my code.
I managed to make it work, but it is way too long and redundant. Is there a way I can do this in a short way?
You may want to have a look at one of the following standard commands:
getopts is a Bash builtin. It is newer and simple to use, but does not support long options (--option).
getopt is an external program which may involve a little more glue code. There are different implementations. getopt usually supports long options.
This is a small getopts example (modified one of the examples from this external site):
#!/bin/bash
flag=off
dir=
# iterate over each option with getopts:
while getopts fd: opt
do
case "$opt" in
f) flag=on;;
d) dir="$OPTARG";;
*) echo >&2 "usage: $0 [-f] [-d directory] [file ...]"
exit 1;;
esac
done
# remove all positional pararmeters we already
# handled from the command line:
shift $(( expr $OPTIND - 1 ))
# main part of your program, remaining arguments are now in
# $# resp. $0, $1, ...
I'd like to suggest another snippet that is a lot simpler to read than yours, because it exactly depicts the only two valid cases you specified in your comment:
If I want to "call" my script it has to look like this: script.sh -n +number -p file.txt. file.txt must be the last argument, however, -n and -p can be switched.
So the cases are ($0 to $4):
script.sh -n +number -p file.txt
script.sh -p -n +number file.txt
It uses only if and Bash's logical operators:
#!/bin/bash
if ! { [[ "$1" = "-n" ]] && [[ "$2" =~ ^-[0-9]+$ ]] && [[ "$3" = "-p" ]] && [[ "$4" =~ ".txt"$ ]] ; } &&
! { [[ "$2" = "-n" ]] && [[ "$3" =~ ^-[0-9]+$ ]] && [[ "$1" = "-p" ]] && [[ "$4" =~ ".txt"$ ]] ; }
then
echo "Error" && exit 1
fi
Notes:
The group ({, }) syntax expects a ; at the end of its list.
You have to use a regex to check for *.txt
The number regex you gave will require the number to start with a -, while in your specification you say +.

unary operator expected with more than 1 argument

for var in "$#"
do
if test -z $var
then
echo "missing operand"
elif [ -d $var ]
then
echo "This is a directory"
elif [ ! -f $var ]
then
echo "The file does not exist"
else
basename=$(basename $var)
dirname=$(readlink -f $var)
inodeno=$(ls -i $var| cut -d" " -f1)
read -p "remove regular file $#" input
if [ $input = "n" ]
then exit 1
fi
mv $var "$var"_"$inodeno"
echo "$basename"_"$inodeno":"$dirname" >> $HOME/.restore.info
mv "$var"_"$inodeno" $HOME/deleted
fi
done
**Hello, the above code is trying to mimic the rm command in unix. Its purpose is to remove the file .
Eg if I type in bash safe_rm file1 , it works however if type in
bash safe_rm file1 file 2 , it prompts me to remove file 1 twice and gives me a unary operater expected for line 27(if [ $input = "n" ]).
Why does it not work for two files, ideally I would like it to prompt me to remove file1 and file 2.
Thanks
read -p "remove regular file $#" input
should probably be
read -p "remove regular file $var" input
That's the basic.
And this is how I'd prefer to do it:
for T in "$#"; do
if [[ -z $T ]]; then
echo "Target is null."
elif [[ ! -e $T ]]; then
echo "Target does not exist: $T"
elif [[ -d $T ]]; then
echo "Target can't be a directory: $T"
else
BASE=${T##*/}
DIRNAME=$(exec dirname "$T") ## Could be simpler but not sure how you want to use it.
INODE_NUM=$(exec stat -c '%i' "$T")
read -p "Remove regular file $T? "
if [[ $REPLY == [yY] ]]; then
# Just copied. Not sure about its logic.
mv "$T" "${T}_${INODE_NUM}"
echo "${BASE}_${INODE_NUM}:${DIRNAME}" >> "$HOME/.restore.info"
mv "${T}_${INODE_NUM}" "$HOME/deleted"
fi
fi
done

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