Loop through files in a directory

Shell Programming and Scripting
1

Hello

How do I loop through files in a specific directory ?

This script is not working!

#! /bin/bash
FILES=/usr/desktop/input/*
For f in $FILES;
do
awk '-v A="$a" -v B="$b" {$6=($1-64)/2 ;$7=((10^($6/10))/A)^(1/B) ; print}' OFS="\t" $f > /root/Desktop/output/$f.txt;
done

Orginal txt file:

$1      $2            $3             $4
74   3.99166 101.37082  2.000
74   3.99166 101.37834  2.000
75   3.98416 101.37082  2.000
75   3.98416 101.37834  2.000
81   3.96916 101.29571  2.000
  0   3.96166 101.28820  2.000
 82   3.96166 101.29571  2.000
 85   3.96167 101.31073  2.000

Expected result:

$1         $2             $3                $4                  $5        $6
74	3.99166	101.37082	2.000		5	0.0748783
74	3.99166	101.37834	2.000		5	0.0748783
75	3.98416	101.37082	2.000		5.5	0.0804649
75	3.98416	101.37834	2.000		5.5	0.0804649
81	3.96916	101.29571	2.000		8.5	0.12391
0	3.96166	101.28820	2.000		-32	0.000364633
82	3.96166	101.29571	2.000		9	0.133155
85	3.96167	101.31073	2.000		10.5	0.165237

Thanks in advance

2

There are no upper case letters in bash keywords.

Second, your awk command line options are improperly quoted so that they and the awk script form a single token behind a leading dash.

Did running this code not generate errors? If so, always share those. They save everyone time and effort.

Regards,
Alister

3

Hi
First of all thanks for your response.

-I changed uppercase letter to lowercase, but not working again!
-I already run awk script lonely, its ok.
-The cod is not working, because it can not find input directory.

4

make sure that files exists using this

$ for f in $FILES; do echo $f; done

and where did you define variable a and b ?

1 Like
5

In addition, note that:

FILES=/usr/desktop/input/*
For f in $FILES;

is not the same as:

for f in /usr/desktop/input/*

Obviously For should be for (lowercase) like alister notes, but also, the content of the unquoted variable expansion $FILES is subject to field splitting (default: space, TAB or newline), which may lead to erroneous results and which will not occur with the second form...

1 Like
6

Hi friend
Thanks for your consideration.

when I run the code without copy the results, it is ok.

#! /bin/bash
FILES=/root/Desktop/decoder/input/*
for f in $FILES
do
awk '{$6=($1-64)/2 ;$7=((10^($6/10))/250)^(1/1.2) ; print}' OFS="\t" "$f";
done

But when I wanna save the results in separate txt files, it is not working.

#! /bin/bash
FILES=/root/Desktop/decoder/input/*
for f in $FILES
do
awk '{$6=($1-64)/2 ;$7=((10^($6/10))/250)^(1/1.2) ; print}' OFS="\t" "$f" > "/root/Desktop/decoder/input/out/"$f".txt "
done

I got this error:

[root@localhost decoder]# t1
./t1: line 6: /root/Desktop/decoder/input/out//root/Desktop/decoder/input/out.txt: No such file or directory
./t1: line 6: /root/Desktop/decoder/input/out//root/Desktop/decoder/input/SG1140103020247.CAP98RE.txt: No such file or directory
[root@localhost decoder]#

Furthermore, I tried to put output directory after done , but it is also not working.

I have a lot of files in Input and I want to have the results of all the files in separate folder.

Thanks in advance.

7

If you are going to specify the path to the target directory in your redirection, then you need to strip directories from $f and only use the basename.

Regards,
Alister

8

Or you could make the destination directory before trying the redirect:

#! /bin/bash
FILES=/root/Desktop/decoder/input/*
for f in $FILES
do
  mkdir -p /root/Desktop/decoder/input/out$(dirname "$f")
  awk '{$6=($1-64)/2 ;$7=((10^($6/10))/250)^(1/1.2) ; print}' OFS="\t" "$f" > /root/Desktop/decoder/input/out"${f}.txt"
done