0

I'm using a blackbox CLI based on Bash and I'm not entirely sure what stuff I can use. Brace expansion doesn't work, and with it goes my ability to do loops without listing the arguments explicitly, which is something I was trying to avoid by looping to start with.

for x in {1..5}
do
    for y in {a..c}
    do
    echo $HOME$x$y
    done
done

How do I run something like this without brace expansion and without listing the arguments explicitly? Environment variables should also work, that's why I appended a random $HOME to the example.

Please feel free to provide different alternatives (AWK, sed) as I'm not entirely sure what will and what won't work.

  • 1
    Do you have access to the jot command? – Fox Mar 12 at 1:13
  • 3
    So this appears to be not based on Bash based on your description; what makes you think that it is? Is there any further detail available about the system, the shell that's in it, or the tools that are available there? – Michael Homer Mar 12 at 2:02
  • @MichaelHomer It was an assumption made based on other things not relevant here. I do not claim to have been a reasonable assumption, but it was one I did. I was wrong. Thank you very much, this prompted me to make sure and find out the truth. – CharacterClass Mar 12 at 9:57
0

You'd better use jot as commented. Here is a (not so pretty) awk implementation.

#!/usr/bin/awk -f
BEGIN{
    for(i=1;i<5;i++)
        for(j=97;j<100;j++)
            printf "%s%d%c ",ENVIRON["HOME"],i,j;                               
    print;
}

or (you may also use the -v option of awk to assign shell variables to awk variables)

#!/bin/bash
awk -f /dev/fd/3 3<< EOF                                                                                                                                                                                    
BEGIN{
    for(i=1;i<5;i++)
        for(j=97;j<100;j++)
            printf "$HOME%d%c ",i,j;
    print;
}
EOF
0

If you're sure you run bash, maybe brace expansion isn't enabled.

Check it with by using

echo $-
himBHs

In the shell I'm using, the option B is set, indicating that brace expansion is enabled.

You can set the brace expansion by using one of these commands:

set -o braceexpand
set -B

In this case I don't need to loop over the letter or numbers:

echo {1..5}{a..c}
1a 1b 1c 2a 2b 2c 3a 3b 3c 4a 4b 4c 5a 5b 5c

or disable it by using either

set +o braceexpand
set +B

leading to

echo {1..5}{a..c}
{1..5}{a..c}

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