Reading data from file to execute Shell Script - shell

I have a 'testfiles' files that has list of files
Ex-
Tc1
Tc2
calling above file in script
test=`cat testfiles`
for ts in $test
do
feed.sh $ts >>results
done
This script runs fine when there only 1 test file in 'testfiles',but when there are multiple files ,it fails with 'file not found'
Let me know if this is correct approach

you ll have to read files one by one since you are taking testfiles='Tc1 Tc2' cat is searching for file named 'Tc1 Tc2' which does not exist so use cut command with " " as the delimiter and rad files one by one in a loop.or u can use sed command also to seperate file names

Your approach should work if the filenames have no spaces or other tricky characters. An approach that handles spaces in file names successfully is:
while IFS= read -r ts
do
feed.sh "$ts" >>results
done <testfiles
If your file names have newline characters in them, then the above won't work and you would need to create testfiles with the names separated by a null character in place of a newline.
Let's consider the original code. When bash substitutes for $test in the for statement, all the file names appear on the same line and bash will perform word splitting which will make a mess of any file names containing white space. The same happens on the line feed.sh $ts. Since $ts is not quoted, it will also undergo word splitting.

Related

Using space-separated arguments from a field in a tab-separated file

I'm writing a shell script intended to edit audio files using the sox command. I've been running into a strange problem I never encountered in bash scripting before: When defining space separated effects in sox, the command will work when that effect is written directly, but not when it's stored in a variable. This means the following works fine and without any issues:
sox ./test.in.wav ./test.out.wav delay 5
Yet for some reason the following will not work:
IFS=' ' # set IFS to only have a tab character because file is tab-separated
while read -r file effects text; do
sox $file.in.wav $file.out.wav $effects
done <in.txt
...when its in.txt is created with:
printf '%s\t%s\t%s\n' "test" "delay 5" "other text here" >in.txt
The error indicates this is causing it to see the output file as another input.
sox FAIL formats: can't open input file `./output.wav': No such file or directory
I tried everything I could think of: Using quotation marks (sox "$file.in.wav" "$file.out.wav" "$effects"), echoing the variable in-line (sox $file.in.wav $file.out.wav $(echo $effects)), even escaping the space inside the variable (effects="delay\ 5"). Nothing seems to work, everything produces the error. Why does one command work but not the other, what am I missing and how do I solve it?
IFS does not only change the behavior of read; it also changes the behavior of unquoted expansions.
In particular, unquoted expansions' content are split on characters found in IFS, before each element resulting from that split is expanded as a glob.
Thus, if you want the space between delay and 5 to be used for word splitting, you need to have a regular space, not just a tab, in IFS. If you move your IFS assignment to be part of the same simple command as the read, as in IFS=$'\t' read -r file effects text; do, that will stop it from changing behavior in the rest of the script.
However, it's not good practice to use unquoted expansions for word-splitting at all. Use an array instead. You can split your effects string into an array with:
IFS=' ' read -r -a effects_arr <<<"$effects"
...and then run sox "$file.in.wav" "$file.out.wav" "${effects_arr[#]}" to expand each item in the array as a separate word.
By contrast, if you need quotes/escapes/etc to be allowed in effects, see Reading quoted/escaped arguments correctly from a string

How to save files' names containing spaces to an array in bash?

Let's say that there are 3 files in a directory: file1, file 2, file 3.
I must use ls to get the file names and save them to an array. The problem is that, for example, bash sees the name file 2 as two separate elements: file and 2, while file1 is properly interpreted.
I understand that bash uses spaces as separators of array elements.
Is it possible to change the separator temporally in the script to double quotes for example?
It would solve the problem 'cause in that case it would simply be the matter of using ls with -Q option.

Single file contain files name and scores | text processing

I have a folder called files that has 100 files, each one has one value inside;such as: 0.974323
This my code to generate those files and store the single value inside:
DIR="/home/XX/folder"
INPUT_DIR="/home/XX/folder/eval"
OUTPUT_DIR="/home/XX/folder/files"
for i in $INPUT_DIR/*
do
groovy $DIR/calculate.groovy $i > $OUTPUT_DIR/${i##*/}_rates.txt
done
That will generate 100 files inside /home/XX/folder/files, but what I want is one single file that has in each line two columns separated by tab contain the score and the name of the file (which is i).
the score \t name of the file
So, the output will be:
0.9363728 \t resultFile.txt
0.37229 \t outFile.txt
And so on, any help with that please?
Assuming your Groovy program outputs just the score, try something like
#!/bin/sh
# ^ use a valid shebang
# Don't use uppercase for variables
dir="/home/XX/folder"
input_dir="/home/XX/folder/eval"
output_dir="/home/XX/folder/files"
# Always use double quotes around file names
for i in "$input_dir"/*
do
groovy "$dir/calculate.groovy" "$i" |
sed "s%^%$i\t%"
done >"$output_dir"/tabbed_file.txt
The sed script assumes that the file names do not contain percent signs, and that your sed recognizes \t as a tab (some variants will think it's just a regular t with a gratuitous backslash; replace it with a literal tab, or try ctrl-v tab to enter a literal tab at the prompt in many shells).
A much better fix is probably to change your Groovy program so that it accepts an arbitrary number of files as command-line arguments, and includes the file name in the output (perhaps as an option).

Modify text file based on file's name, repeat for all files in folder

I have a folder with several files named : something_1001.txt; something_1002.txt; something_1003.txt; etc.
Inside the files there is some text. Of course each file has a different text but the structure is always the same: some lines identified with the string ">TEXT", which are the ones I am interested in.
So my goal is :
for each file in the folder, read the file's name and extract the number between "_" and ".txt"
modify all the lines in this particular file that contain the string ">TEXT" in order to make it ">{NUMBER}_TEXT"
For example : file "something_1001.txt"; change all the lines containing ">TEXT" by ">1001_TEXT"; move on to file "something_1002.txt" change all the lines containing ">TEXT" by ">1002_TEXT"; etc.
Here is the code I wrote so far :
for i in /folder/*.txt
NAME=`echo $i | grep -oP '(?<=something_/).*(?=\.txt)'`
do
sed -i -e 's/>TEXT/>${NAME}_TEXT/g' /folder/something_${NAME}.txt
done
I created a small bash script to run the code but it's not working. There seems to be syntax errors and a loop error, but I can't figure out where.
Any help would be most welcome !
There are two problems here. One is that your loop syntax is wrong; the other is that you are using single quotes around the sed script, which prevents the shell from interpolating your variable.
The grep can be avoided, anyway; the shell has good built-in facilities for extracting the base name of a file.
for i in /folder/*.txt
do
base=${i#/folder/something_}
sed -i -e "s/>TEXT/>${base%.txt}_TEXT/" "$i"
done
The shell's ${var#prefix} and ${var%suffix} variable manipulation facility produces the value of $var with the prefix and suffix trimmed off, respectively.
As an aside, avoid uppercase variable names, because those are reserved for system use, and take care to double-quote any variable whose contents may include shell metacharacters.

Programmatically delete all text between 2 characters in osx terminal

I have a thousand of txt files
1.txt
2.txt
3.txt
in each files, several times I have tags among my text:
{somethinghere...blablabla} than the text I want to keep than again {somethinghere...blablabla}
I'm not very pratical in mac osx command line, can someone help me to write a command opening each file, parsing it, and deleting all text included by two "{"?
To be clear:
First of all I need to open each file, than parse the text. When the loop finds a "{" it starts deleting till it founds a "}". When done parsing it saves and close the file. That's what I need to do.
$ sed -i.bak -e 's#{[^}]*}##g' *.txt
-i.bak make a backup copy of each modified files. If you don't want backups, on OsX use -i'' (the quotes are not necessary on Linux)
in substitutions, the delimiter can be another character than /, here I choose #, so : s#<REGEX>#<REMPLACEMENT># (the basic form for substitutions are s///)
In the regex, we search a litteral { and all but not a } with [^}]. * means 0 or more occurences. Last, we search the closing } and we replace the matching part by nothing, so it delete what was matching
the g modifier #the end means not only one match but all

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