I have a bash script like this :
usage="setup.sh [-localsource path to dir] [-help]";
for i in $#
do
if [ "$localSourceOpt" = 1 ]
then
localSource=$i
localSourceOpt=0;
fi
if [ "$i" = "-localsource" ]
then
localSourceOpt=1;
fi
if [ "$i" = "-help" ]
then
echo "$usage";
exit;
fi
done
which requires on argument e.g
setup.sh -localsource PATH
what I need is to add another argument which MIGHT have multiple argument values e.g
setup.sh -localsource PATH -locbranches one two three
What I should do to capture values passed for argument "-locbranches"
thanks in advance
I note that you're having to code a lot of logic to handle the simplest command-line argument mechanism, and I'd perhaps suggest using the bash getopts functionality instead.
This makes the single argument option work trivial. For multiple arguments it doesn't work well, and you would have to quote the args e.g. -option "1 2 3". However it does handle multiple arguments in the following scenario.
setup.sh -localsource PATH one two three
i.e. the one two three aren't linked to any command line option. An alternative is to specify the option for each argument e.g.
setup.sh -localsource PATH -locbranch one -locbranch two -locbranch three
You can do a switch with 4 cases ( -localsource , -locbranches, -help and default) and in each case you should enter in one state,
for i in $#; do
case "$i" in
"-help") echo "$usage"
;;
"-localsource") STATE="localsource"
;;
"-locbranches") STATE="locbranches"
;;
*)
if [ "$STATE" == "localsource" ]; then
PATH=$i
elif [ "$STATE" == "locbranches"]; then
# do something with argv from locbrances
else
echo "Wrong state!"
fi
;;
esac
done
Related
I'm a Bash newbie, and I'm puzzling through a Bash script where I see this:
while [ $# -ge 2 ]
if [ "x$1" = "x-a" ]; then
echo "STR_A = $2" >>tmpFile.txt
...do more stuff...
elif [ "x$1" = "x-b" ]; then
echo "STR_B = $2" >>tmpFile.txt
...do more stuff...
else
usage
done
The script takes in four (or five?) command line arguments, and that usage function is:
usage() {
echo "usage: myscript -a STR_A | -b STR_B" 1>&2
exit 1
}
So suppose I ran the script like this:
me#ubuntu1:~$./myscript -A apple -B banana
I'm guessing that this code processes the script's command line arguments. I think that the outer while() loop steps through the command line arguments after argument 1, which would be myscript. The inner if() statements check to see an -a or -b flag is used to supply arguments, and then records the text string that follows in tmpFile.txt. Anything outside of those parameters is rejected and the script exits.
A lot of these assumptions rest on the bet that the outer while() loop...
while [ $# -ge 2 ]
...means "parse the BASH argv[] after the first argument", (to put this in C terms.) If that's not a correct assumption, then I have no idea what's going on here. Any feedback is appreciated, thank you!
Some code explanation.
while [ $# -ge 2 ]
There is a missing do for the loop.
This should loop forever if there are two or more arguments, unless shift is used. If there are less than two arguments, the loop does not even start.
if [ "x$1" = "x-a" ]; then
In distant past, it was common to prevent empty strings by adding an extra letter. Nowadays you would if [ "$1" = "-a" ]; then.
else
usage
Note that the usage is called from within the loop. So, if I would call the script as myscript -a, I would not get a usage message. On the other hand, if I would myscript bla bla, I would get an endless stream of error messages, which is probably not what you want.
I would seriously edit the script; determine whether the while is indeed a loop-forever or whether it is used instead of an if, and try the getops for argument parsing.
This doesn't help understand the code you're reading, but I do option parsing like this:
# inititialize vars, not strictly required in this case
a=''
b=''
# process options
while getopts "ha:b:" opt; do
case $opt in
a) a=$OPTARG ;;
b) b=$OPTARG ;;
*) usage ;;
esac
done
# shift after the processing
shift $((OPTIND - 1))
# look for error conditions
if [[ -n $a && -n $b ]]; then
echo "only one of -a or -b should be given" >&2
exit 1
fi
getopts is a bash builtin
I wish to create a simple bash script.
buildapp.sh -build1
buildapp.sh -build2
etc
the option build1/2/3/ etc call an external script depending on option.
So something like
buildapp.sh -build1 → script1.sh
buildapp.sh -build2 → script2.sh
I think this is what you are looking for:
if [ "$1" = "-build1" ]; then
path/to/script1.sh
elif [ "$1" = "-build2" ]; then
path/to/script2.sh
elif [ "$1" = "-build3" ]; then
path/to/script3.sh
else
echo "Incorrect parameter"
fi
Another option is to use getops (see An example of how to use getopts in bash)
Solution
#!/bin/bash
./script${1//[!0-9]/}.sh # './' is the path to scriptX.sh, you may need to adjust it
A very tiny solution, that works with every number, by simply referencing the numeric argument suffix. E.g. it calls ./script123.sh with -build123.
Solution (extended)
#!/bin/bash
if [[ '-build' == "${1//[0-9]/}" ]]
then
./script${1//[!0-9]/}.sh
fi
Extends the above version, so that it only runs ./scriptXXX.sh, if the argument prefix is -build
I am making a bash script that you have to give 2 files or more as arguments.
I want to test if the given files exist. I'm using a while loop because I don't know how many files are given. The problem is that the if statement sees the $t as a number and not as the positional parameter $number. Does somebody have a solution?
t=1
max=$#
while [ $t -le $max ]; do
if [ ! -f $t ]; then
echo "findmagic.sh: $t is not a regular file"
echo "Usage: findmagic.sh file file ...."
exit
fi
t=`expr $t + 1`
done
You can do it with the bash Special parameter # in this way:
script_name=${0##*/}
for t in "$#"; do
if [ ! -f "$t" ]; then
echo "$script_name: $t is not a regular file"
echo "Usage: $script_name file file ...."
exit 1
fi
done
With "$#" you are expanding the positional parameters, starting from one as separate words (your arguments).
Besides, remember to provide a meaningful exit status (e.g. exit 1 instead of exit alone). If not provided, the exit status is that of the last command executed (echo in your case, which succes, so you're exiting with 0).
And for last, instead of write the script name (findmagic.sh in your case), you can set a variable at the beginning in your script:
script_name=${0##*/}
and then use $script_name when necessary. In this way you don't need to update your script if it changes its name.
I need help with my getopts, i want to be able to run this command ( mount command) only if i pass a flag ( -d in this case).
below output is what i have on my script but it doesn't seem to work.
CHECKMOUNT=" "
while getopts ":d" opt
do
case "$opt" in
d) CHECKMOUNT="true" ;;
usage >&2
exit 1;;
esac
done
shift `expr $OPTIND-1`
FS_TO_CHECK="/dev"
if [ "$CHECKMOUNT" = "true" ]
then
if cat /proc/mounts | grep $FS_TO_CHECK > /dev/null; then
# Filesystem is mounted
else
# Filesystem is not mounted
fi
fi
Your script has a number of problems.
Here is the minimal list of fixes to get it working:
While is not a bash control statement, it's while. Case is important.
Whitespace is important: if ["$CHECKMOUNT"= "true"] doesn't work and should cause error messages. You need spaces around the brackets and around the =, like so: if [ "$CHECKMOUNT" = "true" ].
Your usage of getopts is incorrect, I'm guessing that you mistyped this copying an example: While getopts :d: opt should be: while getopts ":d" opt.
Your usage of shift is incorrect. This should cause error messages. Change this to: shift $((OPTIND-1)) if you need to shift OPTIND.
The bare text unknocn flag seems like a comment, precede it with #, otherwise you'll get an error when using an unknown option.
There is no usage function. Define one, or change usage in your \?) case to an echo with usage instructions.
Finally, if your script only requires a single optional argument, you might also simply process it yourself instead of using getopt - the first argument to your script is stored in the special variable $1:
if [ "$1" = "-d" ]; then
CHECKMOUNT="true"
elif [ "$1" != "" ]; then
usage >&2
exit 1
fi
I already know about getopts, and this is fine, but it is annoying that you have to have a flag even for mandatory arguments.
Ideally, I'd like to be able to have a script which receives arguments in this form:
script.sh [optional arguments] [anything required]
for example
script.sh -rvx output_file.txt
where the script says you HAVE to have an output file. Is there any easy way to do this?
As far as I know, with getopts it would have to look like: script.sh -rvx -f output_file.txt, and that is just not very clean.
I can also use python if necessary, but only have 2.4 available, which is a bit dated.
Don't use the getopts builtin, use getopt(1) instead. They are (subtly) different and do different things well. For you scenario you could do this:
#!/bin/bash
eval set -- $(getopt -n $0 -o "-rvxl:" -- "$#")
declare r v x l
declare -a files
while [ $# -gt 0 ] ; do
case "$1" in
-r) r=1 ; shift ;;
-v) v=1 ; shift ;;
-x) x=1 ; shift ;;
-l) shift ; l="$1" ; shift ;;
--) shift ;;
-*) echo "bad option '$1'" ; exit 1 ;;
*) files=("${files[#]}" "$1") ; shift ;;
esac
done
if [ ${#files} -eq 0 ] ; then
echo output file required
exit 1
fi
[ ! -z "$r" ] && echo "r on"
[ ! -z "$v" ] && echo "v on"
[ ! -z "$x" ] && echo "x on"
[ ! -z "$l" ] && echo "l == $l"
echo "output file(s): ${files[#]}"
EDIT: for completeness I have provided an example of handling an option requiring an argument.
If you are using getops, just shift by $OPTIND-1 after your case statement. Then what is left in $* will be everything else, which is probably what you want.
shift $(( ${OPTIND} - 1 )); echo "${*}"
You're are suffering from illusions; using getopts does not require mandatory arguments prefixed by a flag letter. I tried to find a suitable example from my corpus of scripts; this is a semi-decent approximation. It is called rcsunco and is used to cancel a checkout from RCS. I haven't modified it in a while, I see; I use it quite often (because I haven't migrated from RCS completely, yet).
#!/bin/sh
#
# "#(#)$Id: rcsunco.sh,v 2.1 2002/08/03 07:41:00 jleffler Exp $"
#
# Cancel RCS checkout
# -V print version number
# -n do not remove or rename checked out file (like SCCS unget) (default)
# -r remove checked out file (default)
# -k keep checked out file as $file.keep
# -g checkout (unlocked) file after clean-up
# -q quiet checkout
: ${RCS:=rcs}
: ${CO:=co}
remove=yes
keep=no
get=no
quiet=
while getopts gknqrV opt
do
case $opt in
V) echo "`basename $0 .sh`: RCSUNCO Version $Revision: 2.1 $ ($Date: 2002/08/03 07:41:00 $)" |
rcsmunger
exit 0;;
g) get=yes;;
k) keep=yes;;
n) remove=no;;
q) quiet=-q;;
r) remove=yes;;
*) echo "Usage: `basename $0 .sh` [-{n|g}][-{r|k}] file [...]" 1>&2
exit 1;;
esac
done
shift $(($OPTIND-1))
for file in $*
do
rfile=$(rfile $file)
xfile=$(xfile $rfile)
if $RCS -u $rfile
then
if [ $keep = yes ]
then
if [ -f $xfile ]
then
mv $xfile $xfile.keep
echo "$xfile saved in $xfile.keep"
fi
elif [ $remove = yes ]
then rm -f $xfile
fi
if [ $get = yes ] && [ $remove = yes -o $keep = yes ]
then $CO $quiet $rfile
fi
fi
done
It's only a semi-decent approximation; the script quietly does nothing if you don't supply any file names after the optional arguments. However, if you need to, you can check that the mandatory arguments are present after the 'shift'. Another script of mine does have mandatory arguments. It contains:
...
shift $(($OPTIND - 1))
case $# in
2) case $1 in
install) MODE=Installation;;
uninstall) MODE=Uninstallation;;
*) usage;;
esac;;
*) usage;;
esac
So, that command (jlss) can take optional arguments such as -d $HOME, but requires either install or uninstall followed by the name of something to install. The basic mode of use is:
jlss install program
But the optional mode is:
jlss -d $HOME -u me -g mine -x -p install program
I didn't show all of jlss because it has about 12 options - it isn't as compact as rcsunco.
If you were dealing with mandatory arguments before option arguments, then you'd have to do a bit more work:
You'd pick up the mandatory arguments, shifting them out of the way.
Then you process the optional arguments with the flags.
Finally, if appropriate, you handle the extra 'file name' arguments.
If you are dealing with mandatory arguments interspersed with option arguments (both before and after the mandatory ones), then you have still more work to do. This is used by many VCS systems; CVS and GIT both have the facility:
git -global option command [-sub option] [...]
Here, you run one getopts loop to get the global options; pick up the mandatory arguments; and run a second getopts loop to get the sub-options (and maybe run a final loop over the 'file name' arguments).
Isn't life fun?
And I heard a completely opposite thing, that you shouldn't use getopt, but the getopts builtin.
Cross-platform getopt for a shell script
Never use getopt(1). getopt cannot handle empty arguments strings, or
arguments with embedded whitespace. Please forget that it ever
existed.
The POSIX shell (and others) offer getopts which is safe to use
instead.
Here's yet another way to "Option-ize your shell scripts" (whithout using getopt or getopts):
http://bsdpants.blogspot.com/2007/02/option-ize-your-shell-scripts.html