How can I pass a variable as a string into a function in bash?

Question

I have a small bash script that does simple file modifications and I want to rewrite the code to be more readable. My goal is to pass Commands as strings into a function that loops the command over a Directory.

I've tried to use different methods to escape the "$" or different """ combinations but none really work.

#!/bin/bash
process="/Users/Gernot/Tools/.Process"
output="/Users/Gernot/Tools/2 Output"
input="/Users/Gernot/Tools/1 Input/"

function run {

    for file in "$input$1"/*
    do
        echo "running procedure $1" #echoes which procedure is running
        $2 #does the command for every file in the directory

    done


}



run "PDF Komprimieren" "magick convert \$file -density 110 -compress jpeg -quality 100 \$file"

This is the error I get:

running procedure PDF Komprimieren
convert: unable to open image '$file': No such file or directory @ error/blob.c/OpenBlob/3497.
convert: no decode delegate for this image format `' @ error/constitute.c/ReadImage/556.
convert: no images defined `$file' @ error/convert.c/ConvertImageCommand/3273.

you can use eval, eg. $(eval echo "$input/$1). It looks like you want to loop through your args as well — Rorschach
– Rorschach, Commented Aug 1, 2019 at 6:24
Don't pass commands as strings but make different functions like pdf_komprimieren() and magick_convert() which will be, IMHO, more readable. Even when you get your command evaluated, the spaces in the dirname and perhaps filename will cause more problems. — Walter A
– Walter A, Commented Aug 1, 2019 at 6:24
First, I would like to point out that it is a bad practice. The simple hack would be using the evil eval before $2. — anishsane
– anishsane, Commented Aug 1, 2019 at 6:24
@jenesaisquoi No I don't want to loop through my args. I'll try your tip thanks — user11013363
– user11013363, Commented Aug 1, 2019 at 6:29
Storing commands as strings is hard to get right in complex cases; see BashFAQ #50: I'm trying to put a command in a variable, but the complex cases always fail! — Gordon Davisson
– Gordon Davisson, Commented Aug 1, 2019 at 7:38

Walter A · Accepted Answer · 2019-08-01 06:52:53Z

1

Try using functions like

pdf_komprimieren() {
   find "PDF Komprimieren" -maxdepth 2 -type f -print0 |
     xargs --null -n1 -Ifile magick convert "file" -density 110 -compress jpeg -quality 100 "file"
}

answered Aug 1, 2019 at 6:52

Walter A

20.2k2 gold badges29 silver badges46 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

How can I pass a variable as a string into a function in bash?

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related