I’m a complete noob when it comes to bash, I extracted some timestamps from an xml file using xmlstarlet however its formatted as a space separated string rather than an array. I need them as an array so that I can use them in a for loop. As far as I can tell you can’t do that with xmlstarlet so I need to just convert the string.

I found this thread which says I can use IFS=’ ’ read -a arr <<< “$line” which works for a basic string but not the one I’m trying to use it with:

2023-06-19T00:00:00+01:00 2023-06-18T00:00:00+01:00 2023-06-17T00:00:00+01:00 2023-06-16T00:00:00+01:00 2023-06-15T00:00:00+01:00 2023-06-14T00:00:00+01:00 2023-06-13T00:00:00+01:00 2023-06-10T00:00:00+01:00 2023-06-03T00:00:00+01:00 2023-05-31T00:00:00+01:00 2023-05-27T00:00:00+01:00

If I use the command on this string it only puts the first part in the array so I get 2023-06-19T00:00:00+01:00

I also tried arr=( $line ) which is also suggested in the thread but that does the same thing. Is there another way I can try to convert this, or a way to export from xmlstarlet straight to an array?

  • @INeedManaEnglish
    2•1 year ago

    I need them as an array so that I can use them in a for loop

    I don’t think you need an array then. Arrays are very cool but in general the default IFS for bash loop is a space already

    $ your_xmlstarlet_command
2023-06-19T00:00:00+01:00 2023-06-18T00:00:00+01:00 2023-06-17T00:00:00+01:00 2023-06-16T00:00:00+01:00 2023-06-15T00:00:00+01:00 2023-06-14T00:00:00+01:00 2023-06-13T00:00:00+01:00 2023-06-10T00:00:00+01:00 2023-06-03T00:00:00+01:00 2023-05-31T00:00:00+01:00 2023-05-27T00:00:00+01:00
$ for D in `your_xmlstarlet_command`; do echo "line begin - $D - line end";done
line begin - 2023-06-19T00:00:00+01:00 - line end
line begin - 2023-06-18T00:00:00+01:00 - line end
line begin - 2023-06-17T00:00:00+01:00 - line end
line begin - 2023-06-16T00:00:00+01:00 - line end
line begin - 2023-06-15T00:00:00+01:00 - line end
line begin - 2023-06-14T00:00:00+01:00 - line end
line begin - 2023-06-13T00:00:00+01:00 - line end
line begin - 2023-06-10T00:00:00+01:00 - line end
line begin - 2023-06-03T00:00:00+01:00 - line end
line begin - 2023-05-31T00:00:00+01:00 - line end
line begin - 2023-05-27T00:00:00+01:00 - line end

    If you really need an array

    $ arr=(`your_xmlstarlet_command`)
$ echo ${arr[0]}
2023-06-19T00:00:00+01:00
$ echo ${arr[1]}
2023-06-18T00:00:00+01:00
$ for D in ${arr[@]}; do echo "begin - $D - end"; done
begin - 2023-06-19T00:00:00+01:00 - end
begin - 2023-06-18T00:00:00+01:00 - end
begin - 2023-06-17T00:00:00+01:00 - end
begin - 2023-06-16T00:00:00+01:00 - end
begin - 2023-06-15T00:00:00+01:00 - end
begin - 2023-06-14T00:00:00+01:00 - end
begin - 2023-06-13T00:00:00+01:00 - end
begin - 2023-06-10T00:00:00+01:00 - end
begin - 2023-06-03T00:00:00+01:00 - end
begin - 2023-05-31T00:00:00+01:00 - end
begin - 2023-05-27T00:00:00+01:00 - end

    And just for completeness, when you are changing IFS good idea is to save it in OLDIFS and reset it after the loop. IFS is a special veriable and changing it changes how bash interprets the character it contains

    OLDIFS=$IFS
IFS=$'\n' # when you want to pass a list separated with newlines instead of spaces
for ELEMENT in <list of elements separated with \n>; do <your commands>; done
IFS=$OLDIFS
    • @Infernal_pizzaOPEnglish
      2•1 year ago

      I managed to get it to work in the end but thanks for this, I’ll remember that for next time