In a recent getopts experience, I found myself spending far too much
time on this little problem. I hope someone can help...
So here's the deal.
I want to build have a command line interface that accepts either zero,
one, or many parameters of the same type. Assume the script sends
e-mails to a recipient list. I tried to write the code to handle this, but it
did not work:
commandname -r "user1@tld user2@tld user3@tld"
This did not work because the getopts seemed to parse strings using
space as delimiter regardless of the existence of the surrounding double
or single quotes. This resulted in OPTARGS containing only the first
element of the list. (e.g. user1@tld)
So, I changed the UI to be such that any number (0, 1, or more) of the
-r options can be on the command line.
It successfully grabs every single occurrence of the -r option from the
command line. I created the variable, STRING_LIST, to "accumulate" the
strings.
Is there a better way to do this style of zero, one, or more options of
the same type?
Is there a better way to build a list that does not create anomalies such
as a space character at the beginning or end. (My example above has a
single space character as the 1st character of STRING_LIST, due to fact
it is an empty variable the first time it is referenced on the RHS of
the = sign.)
#####
BTW, I am unable change tools or languages so if you want to suggest
that I use Perl or Ruby or even Java, then please include a example code
(for others to see) otherwise why bother acting like a smarty pants if
you can't display a nice example?
I found my bug. I was mucking up command line data before getopts
even had a chance to get a whack at it! Do'h! <Sheepishly> It was
caused by something I was not showing. Ugh.
My "main" was calling a function "process_command_line()" where this
getopts work was being performed. I was calling it this way:
process_command_line $@
I really thought I was doing it correctly by using $@ instead of $*.
Though, not entirely. Evidently, that variable needs to be double quoted,
to get the expected behavior. Like this:
process_command_line "$@"
I wonder why that is? What was I breaking?
Thanks for the feedback! I'm glad I got straightened out now so that I
could avoid writing additional (and unnecessary) code to work around
my bug.
Hmmm... This makes me wonder if %SOME_LARGE_PERCENTAGE% of
the existing code base in the world is a workaround for what the
programmer did not understand.
The easiest way is make one function "old" style, one "new" style, 'set -vx', then compare output.
Quote:
Originally Posted by duderonomy
Hmmm... This makes me wonder if %SOME_LARGE_PERCENTAGE% of the existing code base in the world is a workaround for what the programmer did not understand.
I don't know the answer to that, but one example I can think of was KDE vs QT. In the past the KDE team did a lot of odd tweakage instead of using QT to its fullest. That changed though. Even if a programmer understands it all there's bound to be hundreds of ways to do something "better" (more efficient, more performant). Wrt scripting reading static guides like the ABS (again), reading fora like these and other peoples scripts helps, the rest is experimenting and "just" gaining experience. And as F/OSS shows, if things can be improved they will be.
There are many places where I can see the syntax description for optargs, which, usually boils down to this:
getopts OPTSTRING VARNAME
where:
OPTSTRING tells getopts which options to expect and where to expect arguments
VARNAME tells getopts which shell-variable to use for option reporting... (2 Replies)
Hello everyone,
I need help in understanding the default value for getopts option's argument in ksh. I've written a short test script:
#!/bin/ksh
usage(){
printf "Usage: -v and -m are mandatory\n\n"
}
while getopts ":v#m:" opt; do
case $opt in
v) version="$OPTARG";;
... (1 Reply)
Is there a way I can specify the name of a list as an argument to a shell script and then use the values of that list name in the script?
I need to do this WITHOUT using case statements.
Something like this:
check.sh list1
#!/bin/bash
list1="www.amazon.com www.google.com"... (9 Replies)
Hi Team,
Here's the situation.
I have approximately 300000 to 500000 jpg files in /appl/abcd/work_dir
mv /appl/abcd/work_dir /appl/abcd/process_dir
The above move command will work if the jpg files count is close to 50000 (not sure). If the count is less this mv command holds good. But if... (14 Replies)
Hi,
I want to capture space as well from the argument
eg:
script.ksh -m "Message from xyz" -e "email@xyz.com"
script.ksh -m 'Message from xyz' -e 'email@xyz.com'
I am parsing using getopts, but for option "m" OPTARG is returning only "Message".
Please use code tags next time for... (9 Replies)
Hi I am using find command --
find "directory1" -type f | xargs -i mv {} "directory2"
to avoid above argument list too long problem.
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Dear Experts,
I have a list of 10K files in a directory. I am not able to execute any commands lile ls -lrt, awk, sed, mv, etc........
I wanna execute below command and get the output. How can I achieve it?? Pls help.
root# awk -F'|' '$1 == 1' file_20120710* | wc -l
/bin/awk: Argument list... (2 Replies)
Hi Gurus
I am trying to figure out (with not much success) how to pass two values to a single getopts argument ... for example
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Hi there, if i have a simple getopts like below ...how can i make it so that if somebody enters more than one -g argument for example, it will error with a " you cannot enter more than one -g" or something like that.?
I want to only allow one instance of a -g or a -h etc ..
while getopts... (1 Reply)
Hi all,
I am parsing command line options using getopts.
The problem is that mandatory argument options following ":" is taking next option as argument if it is not followed by any argument.
Below is the script:
while getopts :hd:t:s:l:p:f: opt
do
case "$opt" in
-h|-\?)... (2 Replies)