mjhjmtu

Suppose I have a graphical program named app. Usage example: app -t 'first tab' -t 'second tab' opens two 'tabs' in that program.

The question is: how can I execute the command (i.e. app) from within a bash script if the number of arguments can vary?

Consider this:

#!/bin/bash
tabs=(
 'first tab'
 'second tab'
)

# Open the app (starting with some tabs).
app  # ... How to get `app -t 'first tab' -t 'second tab'`?

I would like the above script to have an effect equivalent to app -t 'first tab' -t 'second tab'. How can such a bash script be written?

Edit: note that the question is asking about composing command line arguments on the fly using an array of arguments.

Giving the arguments from an array is easy, "$array[@]" expands to the array entries as distinct words (arguments). We just need to add the -t flags. To do that, we can loop over the first array, and build another array for the full list of arguments, adding the -t flags as we go:

#!/bin/bash
tabs=("first tab" "second tab")
args=()
for t in "$tabs[@]" ; do 
 args+=(-t "$t")
done
app "$args[@]"

Use "$@" instead of "$tabs[@]" to take the command line arguments of the script instead of a hard coded list.

tabs=("-t" "one tab" "-t" "second tab")
echo app "$tabs[@]"
app -t one tab -t second tab

So now you should convert your original array to array with "-t" flags. Hope it's not a problem at all.

It's easier with zsh:

#!/bin/zsh -
tabs=(
 'first tab'
 'second tab'
)

app -t$^tabs

That calls app as if you had entered:

app -t'first tab' -t'second tab'

rc, es and fish do that implicitly (zsh's $^array is actually inspired from rc's ^):

In those shells,

app -t$tabs

would do that as well.

To call app as if with

app -t 'first tab' -t 'second tab'

as opposed to

app -t'first tab' -t'second tab'

That is where -t and first tab are two different arguments to app, with zsh:

app $$:--t:^^tabs

using the $array1:^^array2 array-zipping operator where $:--t (minimal form of $var:-default) is used to inline the first array.

Basically the following bash script will read the file which include sites line by line and open each site in a new tab.

#!/bin/bash
while read line
do 
 xdg-open "$line"
done < /root/file

Usage

./script.sh sites