Created
November 26, 2010 14:17
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Completely safe find
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#!/bin/bash | |
# Filenames can contain *any* character except only null (\0) and slash (/); | |
# here's some general rules to handle them: | |
# | |
# $'...' can be used to create human readable strings with escape sequences. | |
# | |
# ' -- ' in commands is necessary to separate arguments from filenames, since | |
# filenames can start with '--', and would therefore be handled as parameters. | |
# To handle parameters properly (like GNU tools) use `getopt`. | |
# | |
# `find` doesn't support this syntax, so we use `readlink` to get an absolute | |
# path which by definition starts with slash. | |
# | |
# The "$()" construct strips trailing newlines, so we have to add a different | |
# character and then strip it outside the "$()" construct. | |
# | |
# `IFS=` is necessary to avoid that any characters in IFS are stripped from | |
# the start and end of $path. | |
# | |
# '-r' avoids interpreting backslash in filenames specially. | |
# | |
# '-d $'\0' splits filenames by the null character. | |
# | |
# '-print0' separates find output by null characters. | |
# | |
# Variables inside '$()' have to be quoted just like outside this construct. | |
# | |
# Use process substitution with "<(" instead of pipes to avoid broken pipes. | |
# | |
# Use file descriptor 9 for data storage instead of standard input to avoid | |
# greedy commands like `cat` eating all of it. | |
set -o errexit | |
set -o nounset | |
set -o noclobber | |
test_file_name=$'--$`\! *@ \a\b\e\E\f\r\t\v\\\"\' \n' | |
test_dir_path="$test_file_name" | |
test_file_path="${test_dir_path}/${test_file_name}" | |
mkdir -- "$test_dir_path" | |
touch -- "$test_file_path" | |
absolute_dir_path_x="$(readlink -fn -- "$test_dir_path"; echo x)" | |
absolute_dir_path="${absolute_dir_path_x%x}" | |
exec 9< <( find "$absolute_dir_path" -type f -print0 ) | |
while IFS= read -rd $'\0' -u 9 | |
do | |
file_path="$(readlink -fn -- "$REPLY"; echo x)" | |
file_path="${file_path%x}" | |
echo "START${file_path}END" | |
done | |
rm -- "$test_file_path" | |
rmdir -- "$test_dir_path" |
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Further development will be at https://github.com/l0b0/tilde/blob/master/examples/safe-find.sh