Linux bash scripting: sorting a list to use

Question

I'm implementing a sort-function in my script, but I have trouble in doing so:

what I want to achieve is the following:

bash script --sort 44 55 1 23 44

output:

Pinging to 192.168.1.1 succes
Pinging to 192.168.1.23 failed
Pinging to 192.168.1.44 failed
Pinging to 192.168.1.55 failed

The pinging and stuff already works, I just don't know how to make a list with the arguments, sort them and (save the list) then use them in the ping command (by using for var in $SORTEDLIST do <ping-command> done.

I already had this:

    SORTEDLIST="$SORTEDLISTS $@"
    for var in $SORTEDLISTS
    do
            echo "$var"
    done | sort -n -u

The echo was just a test, but there I'll have to save the list somehow. Any ideas?

@ColOfAbRiX The sort function needs something to sort on: it doesn't directly work on lists, so no, that won't do it. The echoed vars are now sorted, but I want to be able to put them in a sorted list. — Kryptonous
– Kryptonous, Commented Jun 1, 2015 at 13:18
@Kryptonous In my answer I suppose that you have just the last number of the IP, the one you provide on the command line. So you can sort it and complete later the full IP. Or maybe I misunderstood the problem and/or the context — ColOfAbRiX
– ColOfAbRiX, Commented Jun 1, 2015 at 13:40
No, @ColOfAbRiX, you're answer is correct as well. Pity I can only choose one solution! They're both really good. Actually, yours might even be slightly better in my situation. And indeed, I only use the last number of the IP. Thanks! — Kryptonous
– Kryptonous, Commented Jun 1, 2015 at 14:56

Community · Accepted Answer · 2017-05-23 11:43:45Z

2

$@ is an array (of all script parameters), so you can sort using

OIFS="$IFS" # save IFS
IFS=$'\n' sorted=($(sort -n <<<"$*"))
IFS="$OIFS" # restore IFS

and then use the result like so:

for I in "${sorted[@]}"; do
    ...
done

Explanation:

IFS is an internal shell variable (internal field separator) which tells the shell which character separates words (default is space, tab and newline).
$'\n' expands to a single newline. When the shell expands $*, it will now put a new line between each element.
sort -n <<< pipes the "one argument per line" to sort which sorts numerically (-n)
sorted=($(...)) creates a new array with the result of the command ...

6 Comments

123 Over a year ago

Should take a copy of IFS before changing it and change it back when done.

Aaron Digulla Over a year ago

@User112638726: Like this?

123 Over a year ago

Yep, always best to return things to how you found them!

Kryptonous Over a year ago

Can I use this "${sorted[@:1]" to start from the 2nd argument?

Aaron Digulla Over a year ago

The syntax is probably "${sorted[@]:1}". See unix.stackexchange.com/questions/68322/… Or you can use shift before the assignment of sorted to remove the first element from $*

|

ColOfAbRiX · Accepted Answer · 2015-06-01 13:37:03Z

1

This script takes the command line arguments, it splits them one per line tr ' ' '\n', sort them numerically tr ' ' '\n' and print them :

#!/bin/bash
LIST="$@"

for I in $(echo "$LIST" | tr ' ' '\n' | sort -g)
do
    echo $I
    echo "192.168.0.1.$I"
done

edited Jun 1, 2015 at 13:37

answered Jun 1, 2015 at 13:19

ColOfAbRiX

1,0691 gold badge13 silver badges29 bronze badges

Collectives™ on Stack Overflow

Linux bash scripting: sorting a list to use

2 Answers 2

6 Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

6 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related