How to make a range of values in a loop change name of file in bash

Question

Its about 2500 CSV files who need to be replaced with and comma values and i need a script to select a range.

R000001.CSV....R000499 in 5 directories but filename needs to be changed with the for next loop.

I need some advice to make this script works.

BTW _1 its a mark for the processed files.

read -p "First Value: " f
read -p "Last Value: " l
read -p "Secuence $f to $l ... is correct press <enter> to continue or Ctrl+C to cancel"
for a in {$f..$l..1}
  do
     tr -d '\r' ';'< R*$f.CSV > R*$f_1.CSV

 done

"who need to be replaced with and comma values" Please clarify. — John1024
– John1024, Commented Nov 10, 2015 at 3:21

John1024 · Accepted Answer · 2015-11-10 17:47:50Z

1

Try:

for a in $(seq -f '%06.0f' "$f" "$l")
do
    echo tr -d '\r' ';' <R*$a.CSV >R*${a}_1.CSV
done

Notes:

The expression {$f..$l..1} will not work because variables cannot be put inside of a brace expansion.
The utility seq can be used in place of brace expansion. With the -f option, we can select the format that matches your file names.
Inside the loop, you want to reference $a rather than $f.
The expression $f_1 will not work as you expect. Both _ and 1 are legal characters in shell variable names. Consequently, the shell will try to find a shell variable named f_1 and expand it. That is not what you want. Using braces around a shell variable name, such as ${f}_1, avoids this.

Without `seq`

for ((i=$f; i<=$l; i++)) do j=$(printf '%06i' $i); tr '\r' ';'<"R$j.CSV" >"R${j}_1.CSV"; done

Or, written over multiple lines for clarity:

for ((i=$f; i<=$l; i++))
do
    j=$(printf '%06i' $i)
    tr '\r' ';'<"R$j.CSV" >"R${j}_1.CSV"
done

edited Nov 10, 2015 at 17:47

answered Nov 10, 2015 at 3:28

John1024

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3 Comments

Ralcala Over a year ago

thanks John but seq command does not exists in osx snow leopard so i research more and now i got this.. for ((i=$f; i<=$l; i++)) do tr '\r' ';'< R*$i.CSV > R*${i}_1.CSV done

John1024 Over a year ago

@Ralcala Yes, those * could cause problems. See the updated answer for a variation on your code that should work (it works for me). Separately, for whatever its worth, I checked the man pages that Apple puts online and it appears that, in the future, you will be able to use seq: Apple includes seq in the current OSX version.

Ralcala Over a year ago

Thank you very much for your time John and your instructions. The script works thank you again.

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