I would like to use the cut command to extract some columns of a csv file.
However, instead of having my criterion hard-coded, I would like to take them from a bash variable.
Without a variable, my command would look like the following:
cut -d';' -f 1-8,20,22 "$input_file" > ANFR_reduced.csv
However, when I store the critera -f 1-8,20,22 within a bash variable, my cut command fails to execute correctly (error fields are numbered from 1)
criteria_col="-f 1-8,20,22"
cut -d';' "$criteria_col" "$input_file" > ANFR_reduced.csv
Any ideas to why this is not working, please?
If you enable debug mode (set -xv) you'll see what bash sees:
$ touch some_file
$ criteria_col="-f 1-8,20,22"
$ set -xv
$ cut -d';' "$criteria_col" some_file
+ cut '-d;' '-f 1-8,20,22' some_file
^^^^^^^^^^^^^^
cut: fields are numbered from 1
Try 'cut --help' for more information.
Notice that -f 1-8,20,22 is being treated as a single string '-f 1-8,20,22' which in turn causes the error.
One simple fix would be to move the -f from the variable to the command line, eg:
$ criteria_col="1-8,20,22"
$ cut -d';' -f "$criteria_col" some_file
^^
+ cut '-d;' -f 1-8,20,22 some_file
$ # no error; no output since my file is empty
If you need the -f to be part of the criteria then I'd recommend F.Hauri's comment/suggestion of using an array.