shell script arguments?

frieza · 09-02-2011, 04:38 PM

here's a little script i wrote for importing batches of mysql databases and creating users and privileges for them

the question is simple, how do i take the parts in brackets and accept them as arguments
like

Code:

./script.sh -rp {mysql_root_password} -nup {password_for_new_users}

and generate an error message if either of those arguments is omitted

Code:

for file in `ls *.sql`
do
part1=`echo $file | cut -d . -f 1`
part2=`echo $file | cut -d . -f 2`
mysql -hlocalhost -uroot -p{mysql_root_password} << eof
create database `echo $part1`;
create user '`echo $part1`'@localhost;
GRANT SELECT ,INSERT ,UPDATE ,DELETE ,CREATE ,DROP ,INDEX ,ALTER ,CREATE TEMPORARY TABLES,LOCK TABLES ON `echo $part1`.* TO '`echo $part1`'@'localhost';
set password for '`echo $part1`'@localhost = password('{password_for_new_users}');
flush privileges;
eof
mysql -hlocalhost -u`echo $part1` -p{password_for_new_users} `echo $part1` < $file
done

ta0kira · 09-02-2011, 04:47 PM

If you're using bash look at help getopts. I don't use getopts, so I don't have an example for you.
Kevin Barry

KenJackson · 09-02-2011, 08:26 PM

Yeah, you could use getopts.
But here's my favorite way to handle this:

Code:

#!/bin/sh
function error_exit() { echo "ERROR: $*" 1>&2; exit 1; }

ROOTPASS= USERPASS=
while test $# -gt 0; do
    case "$1" in
        -rp)   shift; ROOTPASS="$1"        ;;
        -rp*)         ROOTPASS="${1#-rp}"  ;;
        -nup)  shift; USERPASS="$1"        ;;
        -nup*)        USERPASS="${1#-nup}" ;;
        *)   error_exit "Unknown switch or argument \"$1\"" ;;
    esac
    shift
done
test -z "$ROOTPASS"  &&  error_exit "No root password was given"
test -z "$USERPASS"  &&  error_exit "No user password was given"

# Etcetera

ta0kira · 09-02-2011, 08:57 PM

Quote:

Originally Posted by KenJackson

Yeah, you could use getopts.
But here's my favorite way to handle this:

That's an interesting solution. You might make it a little more flexible, though:

Code:

#!/bin/bash

error_exit() { echo "ERROR: $*" 1>&2; exit 1; }

unset ROOTPASS USERPASS others

while test $# -gt 0; do
    case "$1" in
        -rp)   shift; ROOTPASS="$1"        ;;
        -rp*)         ROOTPASS="${1#-rp}"  ;;
        -nup)  shift; USERPASS="$1"        ;;
        -nup*)        USERPASS="${1#-nup}" ;;
        --)    shift; break ;;
        -*)    error_exit "Unknown switch or argument \"$1\"" ;;
        *)     others=( ${others[@]-} "$1" ) ;;
    esac
    shift
done

others=( ${others[@]-} "$@" )

test -z "$ROOTPASS"  &&  error_exit "No root password was given"
test -z "$USERPASS"  &&  error_exit "No user password was given"

for other in "${others[@]}"; do
  echo "OTHER: $other"
done

# Etcetera

This allows for non-option arguments and the "--" end-of-options separator.
Kevin Barry

David the H. · 09-03-2011, 02:20 AM

If the OP wants to use the real getopts, this page details its use rather well:

http://wiki.bash-hackers.org/howto/getopts_tutorial

As for the above function, it's not a bad solution for a simple script, although in the end it's really just a home-made, simplified getopts-style processor. Unlike getopts, you can personalize your option formats, but on the other hand it won't easily handle option combos (at least not without defining all the possible combinations), or catch missing argument errors without doing further tests.

I'd also like to add my two cents to the above:

Code:

while test $# -gt 0; do

# can be changed to...

while (( $# > 0 )); do

# or even just...

while (( $# )); do

Code:

others=( ${others[@]-} "$1" ) 
others=( ${others[@]-} "$@" )

# can be changed to...

others+=( "$1" )
others+=( "$@" )

Or is there any reason to use ${others[@]-} instead of ${others[@]}? All the first one does is set an empty element if the array was previously empty.

.........

PS to frieza: I posted a comment earlier to your previous thread with some suggestions for improving your script. Check it out.

MTK358 · 09-04-2011, 07:39 PM

The best solution is probably to use getopt (not getopts, but getopt).

Code:

opts="$(getopt --alternative --quiet --shell=bash  -l 'rp:,nup:' -- "$@")"
if [[ $? != 0 ]]
then
    echo "Invalid option syntax" 1>&2
    print_usage 1>&2
    exit 1
fi
eval set -- "$opts"

options_finished="no"
while (( $# > 0 ))
do
    if [[ $options_finished = no ]]
    then
        case "$1" in
            -rp)
                shift
                rootpass="$1"
                ;;
            -nup)
                shift
                userpass="$1"
                ;;
            --)
                options_finished=yes
                ;;
            *)
                echo "Invalid option \"${1}\"" 1>&2
                print_usage 1>&2
                exit 1
                ;;
        esac
    else
        # do somethong with non-option argument in $1
    fi
    shift
done

ta0kira · 09-04-2011, 08:20 PM

Quote:

Originally Posted by MTK358

The best solution is probably to use getopt (not getopts, but getopt).

This doesn't seem much more convenient than the other solutions given, and it depends on an external program.
Kevin Barry

Diantre · 09-06-2011, 08:37 PM

Quote:

Originally Posted by ta0kira

This doesn't seem much more convenient than the other solutions given, and it depends on an external program.

I find getopt convenient when I want a script to handle short and long options (-o, --option), since getopts supports short options only.