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I have some files in a bunch of directories that have a leading dot and thus are hidden. I would like to revert that and strip the leading dot.
I was unsuccessful with the following:
for file in `find files/ -type f`;
do
base=`basename $file`
if [ `$base | cut -c1-2` = "." ];
then newname=`$base | cut -c2-`;
dirs=`dirname $file`;
echo $dirs/$newname;
fi
done
Which fails on the condition statement:
[: =: unary operator expected
Furthermore, some files have a space in them and file returns them split.
Any help would be appreciated.
397
Again, $() is a command substitution which means that it “reassigns the output of a command or even multiple commands; it literally plugs the command output into another context” (Source).
The [[ ... ]] part allows to test a condition using operators. Think of it as an if statement. In your example, you're using the -s operator, which tests that the referenced file is not empty.
(dot) runs a shell script in the current environment and then returns. Normally, the shell runs a command file in a child shell so that changes to the environment by such commands as cd, set, and trap are local to the command file.
There is a built-in function named trim() for trimming in many standard programming languages. Bash has no built-in function to trim string data. But many options are available in bash to remove unwanted characters from string data, such as parameter expansion, sed, awk, xargs, etc.
When to use the Dot Command in Bash? First of, the dot command (.) is not to be confused with a dot file or a relative path notation. For example, the ~/.ssh folder is a hidden folder using the dot file notation, you will need to use ls -a to see that folder.
`sed` command is another option to remove leading and trailing space or character from the string data. The following commands will remove the spaces from the variable, $myVar using `sed` command.
Sometimes it requires to remove characters from the starting and end of the string data which is called trimming. There is a built-in function named trim () for trimming in many standard programming languages. Bash has no built-in function to trim string data.
Bash has no built-in function to trim string data. But many options are available in bash to remove unwanted characters from string data, such as parameter expansion, sed, awk, xargs, etc.
The easiest way to delete something from the start of a variable is to use ${var#pattern}.
$ FILENAME=.bashrc; echo "${FILENAME#.}"
bashrc
$ FILENAME=/etc/fstab; echo "${FILENAME#.}"
/etc/fstab
See the bash man page:
${parameter#word}
${parameter##word}The word is expanded to produce a pattern just as in pathname expansion. If the pattern matches the beginning of the value of parameter, then the result of the expansion is the expanded value of parameter with the shortest matching pattern (the ‘‘#’’ case) or the longest matching pattern (the ‘‘##’’ case) deleted.
By the way, with a more selective find command you don't need to do all the hard work. You can have find only match files with a leading dot:
find files/ -type f -name '.*'
Throwing that all together, then:
find files/ -type f -name '.*' -printf '%P\0' |
while read -d $'\0' path; do
dir=$(dirname "$path")
file=$(basename "$path")
mv "$dir/$file" "$dir/${file#.}"
done
Additional notes:
To handle file names with spaces properly you need to quote variable names when you reference them. Write "$file" instead of just $file.
For extra robustness the -printf '\0' and read -d $'\0' use NUL characters as delimiters so even file names with embedded newlines '\n' will work.
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