Here is a LIST:
List = "abcd 1234 jvm something"
How to get the second element "1234" without looping all the list?
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2 Answers
no spaces between equal sign
$ List="abcd 1234 jvm something"
$ set -- $List
$ echo $2
1234
Some other ways, although not as efficient as using shell's internals
$ echo $List | cut -d" " -f2
1234
$ echo $List | awk '{print $2}'
1234
$ echo $List | sed 's/^.[^ \t]* //;s/ .*//'
1234
$ echo $List | tr " " "\n"|sed -n '2p'
1234
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18@Spawn
set -- $somethingsplits$somethingat the$IFScharacter (by default space) and assigns the split parts to the positional variables$1,$2,... Mar 19, 2010 at 3:44 -
As @BenjaminBannier says in his answer: using set this way may pollute the environment. I.e. by overwriting positional parameters. To suggest it as an answer without explaining what it does is irresponsible.– marklingMay 24 at 10:34
Just to supplement ghostdog's answer: you could also put $List's elements into an array and access the specific list element from there
List="abcd 1234 jvm something"
arr=($List)
echo ${arr[1]}
Note that the array indices are counted 0,1,2,... .
This has the advantage of not polluting the shell environment with too many new variables.
answered Mar 19, 2010 at 4:03
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@BenjaminBannier, how can you select multiple elements. Is there some syntax like ${arr[1,2,3]}$ (not this, since I tried, but like this) or do I need to use a for loop.– KvotheApr 4, 2019 at 12:51
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@Kvothe, you can take a slice from the list and loop over them. E.g.
for v in "${arr[@]:1}"; do echo "$v"; done... (i) takes all array elements"${arr[@]}", (ii) gets a slice of them, consisting of 2nd through last elements"${arr[@]:1}", and (iii) loops each into$v.– marklingMay 24 at 10:44