I use code in !/bin/sh like this:
LIST1="mazda toyota honda"
LIST2="2009 2006 2010"
for m in $LIST1
do
echo $m
done
As you can see this currently prints out only the make of the car. How can I include the year to each "echo" based on the same positions so that I get results like:
mazda 2009
toyota 2006
honda 2010
?
Assuming bash
array1=(mazda toyota honda)
array2=(2009 2006 2010)
for index in ${!array1[*]}
do
printf "%s %s\n" ${array1[$index]} ${array2[$index]}
done
Well, bash does have arrays, see man bash. The generic posix shell does not.
The shell is not precisely a macro processor, however, and so any metaprogramming must be processed by an eval or, in bash, with the ${!variable} syntax. That is, in a macro processor like nroff you can easily fake up arrays by making variables called a1, a2, a3, a4, etc.
You can do that in the posix shell but requires a lot of eval's or the equivalent like $(($a)).
$ i=1 j=2; eval a$i=12 a$j=34
$ for i in 1 2; do echo $((a$i)); done
12
34
$
And for a bash-specific example...
$ a=(56 78)
$ echo ${a[0]}
56
$ echo ${a[1]}
78
$
You can use arrays but just to be different here's a method that doesn't need them:
LIST1="mazda toyota honda"
LIST2="2009 2006 2010"
paste -d' ' <(echo $LIST1 | tr ' ' '\n') <(echo $LIST2 | tr ' ' '\n')
You can use the $IFS var to fake arrays for example (works with any posix compilant shell):
hosts=mingw:bsd:linux:osx # for example you have the variable with all aviable hosts
# the advantage between other methods is that you have still one element and all contens get adressed through this
old_ifs=$IFS #save the old $IFS
IFS=: # say sh to seperate all commands by :
for var in $hosts ; do
# now we can use every element of $var
IFS=$old_ifs
echo $var
done
IFS=$Old_ifs
If you wrap this in a function you can use them like a real array
