CODEWITHSUNDEEP
linuxshellloopsdirectorysh
UberNate
UberNate

Reputation: 2419

How to open all files in a directory in Bourne shell script?

How can I use the relative path or absolute path as a single command line argument in a shell script?

For example, suppose my shell script is on my Desktop and I want to loop through all the text files in a folder that is somewhere in the file system.

I tried sh myshscript.sh /home/user/Desktop, but this doesn't seem feasible. And how would I avoid directory names and file names with whitespace?

myshscript.sh contains:

for i in `ls`
do
    cat $i
done

Upvotes: 1

Views: 2564

Answers (2)

Jonathan Leffler
Jonathan Leffler

Reputation: 753695

Superficially, you might write:

cd "${1:-.}" || exit 1
for file in *
do
    cat "$file"
done

except you don't really need the for loop in this case:

cd "${1:-.}" || exit 1
cat *

would do the job. And you could avoid the cd operation with:

cat "${1:-.}"/*

which lists (cats) all the files in the given directory, even if the directory or the file names contains spaces, newlines or other difficult to manage characters. You can use any appropriate glob pattern in place of * — if you want files ending .txt, then use *.txt as the pattern, for example.

This breaks down if you might have so many files that the argument list is too long. In that case, you probably need to use find:

find "${1:-.}" -type f -maxdepth 1 -exec cat {} +

(Note that -maxdepth is a GNU find extension.)

Avoid using ls to generate lists of file names, especially if the script has to be robust in the face of spaces, newlines etc in the names.

Upvotes: 2

that other guy
that other guy

Reputation: 123460

Use a glob instead of ls, and quote the loop variable:

for i in "$1"/*.txt
do
    cat "$i"
done

PS: ShellCheck automatically points this out.

Upvotes: 1

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