I have a script with a user-entered name, and want to determine whether any directories exist starting with that name.
This code looks like:
runTest() {
if test -d "$name"*; then
echo "Directories starting with $name already exist"
fi
}
It works fine if there is only one such directory:
name=foobar
rm -rf foobar*
mkdir foobar1
runTest # now the code will work
...but it doesn't work if there are multiple matches:
name=foobar
rm -rf foobar*
mkdir foobar1 foobar2
runTest # now the code will emit an error: "test: too many arguments"
How can I make this work with any number of directories, without assuming that one of the matches will always include a specific number (like 1)?
As an example of a working (bash-only -- not /bin/sh compatible) alternative, consider:
if dirs=( "$name"*/ ) && [[ -d ${dirs[0]} ]]; then
echo "Directories starting with $name already exist"
fi
An array assignment works with any number of matches
...but the first entry in the array will be a valid directory only if the glob successfully expanded (and the trailing / in the glob expression prevents it from expanding to anything except directories, so if the result has any directories at all, you know that all elements it expanded to are directories).
If you need something that works for /bin/sh as well, consider the following function:
directoriesExist() { [ -d "$1" ]; }
if directoriesExist "$name"*/; then
echo "Directories starting with $name already exist"
fi
This works because the list of matches expands onto the function's argument list, effectively serving as an alternative to an array.
Because [ is a shell builtin, these globbing-based approaches have much lower constant-factor costs than approaches depending on external tools, which will make them considerably faster overall (except for some corner cases, such as directories so large that it's preferable to stop after the first match is found; where find . -name "$name*" -print -quit may be useful).
Simplest solution:
ls "$name"*/ >/dev/null 2>&1 && echo "Directories starting with $name already exist"
(caution: may not work in some special cases (special characters in file names etc))
Try out this one.
#! /bin/bash -e
name='foobar'
if [ `find . -maxdepth 1 -type d -name "$name*" -print -quit` -gt 1 ]; then
echo "Directories starting with $name already exist"
fi
What command checks if a directory exists or not within a Bash shell script?
To check if a directory exists:
if [ -d "$DIRECTORY" ]; then
echo "$DIRECTORY does exist."
fi
To check if a directory does not exist:
if [ ! -d "$DIRECTORY" ]; then
echo "$DIRECTORY does not exist."
fi
However, as Jon Ericson points out, subsequent commands may not work as intended if you do not take into account that a symbolic link to a directory will also pass this check.
E.g. running this:
ln -s "$ACTUAL_DIR" "$SYMLINK"
if [ -d "$SYMLINK" ]; then
rmdir "$SYMLINK"
fi
Will produce the error message:
rmdir: failed to remove `symlink': Not a directory
So symbolic links may have to be treated differently, if subsequent commands expect directories:
if [ -d "$LINK_OR_DIR" ]; then
if [ -L "$LINK_OR_DIR" ]; then
# It is a symlink!
# Symbolic link specific commands go here.
rm "$LINK_OR_DIR"
else
# It's a directory!
# Directory command goes here.
rmdir "$LINK_OR_DIR"
fi
fi
Take particular note of the double-quotes used to wrap the variables. The reason for this is explained by 8jean in another answer.
If the variables contain spaces or other unusual characters it will probably cause the script to fail.
Always wrap variables in double quotes when referencing them in a Bash script.
if [ -d "$DIRECTORY" ]; then
# Will enter here if $DIRECTORY exists, even if it contains spaces
fi
Kids these days put spaces and lots of other funny characters in their directory names. (Spaces! Back in my day, we didn't have no fancy spaces!)
One day, one of those kids will run your script with $DIRECTORY set to "My M0viez" and your script will blow up. You don't want that. So use double quotes.
Note the -d test can produce some surprising results:
$ ln -s tmp/ t
$ if [ -d t ]; then rmdir t; fi
rmdir: directory "t": Path component not a directory
File under: "When is a directory not a directory?" The answer: "When it's a symlink to a directory." A slightly more thorough test:
if [ -d t ]; then
if [ -L t ]; then
rm t
else
rmdir t
fi
fi
You can find more information in the Bash manual on Bash conditional expressions and the [ builtin command and the [[ compound commmand.
I find the double-bracket version of test makes writing logic tests more natural:
if [[ -d "${DIRECTORY}" && ! -L "${DIRECTORY}" ]] ; then
echo "It's a bona-fide directory"
fi
Shorter form:
# if $DIR is a directory, then print yes
[ -d "$DIR" ] && echo "Yes"
A simple script to test if a directory or file is present or not:
if [ -d /home/ram/dir ] # For file "if [ -f /home/rama/file ]"
then
echo "dir present"
else
echo "dir not present"
fi
A simple script to check whether the directory is present or not:
mkdir tempdir # If you want to check file use touch instead of mkdir
ret=$?
if [ "$ret" == "0" ]
then
echo "dir present"
else
echo "dir not present"
fi
The above scripts will check if the directory is present or not
$? if the last command is a success it returns "0", else a non-zero value.
Suppose tempdir is already present. Then mkdir tempdir will give an error like below:
mkdir: cannot create directory ‘tempdir’: File exists
To check if a directory exists you can use a simple if structure like this:
if [ -d directory/path to a directory ] ; then
# Things to do
else #if needed #also: elif [new condition]
# Things to do
fi
You can also do it in the negative:
if [ ! -d directory/path to a directory ] ; then
# Things to do when not an existing directory
Note: Be careful. Leave empty spaces on either side of both opening and closing braces.
With the same syntax you can use:
-e: any kind of archive
-f: file
-h: symbolic link
-r: readable file
-w: writable file
-x: executable file
-s: file size greater than zero
You can use test -d (see man test).
-d file True if file exists and is a directory.
For example:
test -d "/etc" && echo Exists || echo Does not exist
Note: The test command is same as conditional expression [ (see: man [), so it's portable across shell scripts.
[ - This is a synonym for the test builtin, but the last argument must, be a literal ], to match the opening [.
For possible options or further help, check:
help [
help test
man test or man [
Or for something completely useless:
[ -d . ] || echo "No"
Here's a very pragmatic idiom:
(cd $dir) || return # Is this a directory,
# and do we have access?
I typically wrap it in a function:
can_use_as_dir() {
(cd ${1:?pathname expected}) || return
}
Or:
assert_dir_access() {
(cd ${1:?pathname expected}) || exit
}
The nice thing about this approach is that I do not have to think of a good error message.
cd will give me a standard one line message to standard error already. It will also give more information than I will be able to provide. By performing the cd inside a subshell ( ... ), the command does not affect the current directory of the caller. If the directory exists, this subshell and the function are just a no-op.
Next is the argument that we pass to cd: ${1:?pathname expected}. This is a more elaborate form of parameter substitution which is explained in more detail below.
Tl;dr: If the string passed into this function is empty, we again exit from the subshell ( ... ) and return from the function with the given error message.
Quoting from the ksh93 man page:
${parameter:?word}
If parameter is set and is non-null then substitute its value;
otherwise, print word and exit from the shell (if not interactive).
If word is omitted then a standard message is printed.
and
If the colon : is omitted from the above expressions, then the
shell only checks whether parameter is set or not.
The phrasing here is peculiar to the shell documentation, as word may refer to any reasonable string, including whitespace.
In this particular case, I know that the standard error message 1: parameter not set is not sufficient, so I zoom in on the type of value that we expect here - the pathname of a directory.
A philosophical note:
The shell is not an object oriented language, so the message says pathname, not directory. At this level, I'd rather keep it simple - the arguments to a function are just strings.
if [ -d "$Directory" -a -w "$Directory" ]
then
#Statements
fi
The above code checks if the directory exists and if it is writable.
More features using find
Check existence of the folder within sub-directories:
found=`find -type d -name "myDirectory"`
if [ -n "$found" ]
then
# The variable 'found' contains the full path where "myDirectory" is.
# It may contain several lines if there are several folders named "myDirectory".
fi
Check existence of one or several folders based on a pattern within the current directory:
found=`find -maxdepth 1 -type d -name "my*"`
if [ -n "$found" ]
then
# The variable 'found' contains the full path where folders "my*" have been found.
fi
Both combinations. In the following example, it checks the existence of the folder in the current directory:
found=`find -maxdepth 1 -type d -name "myDirectory"`
if [ -n "$found" ]
then
# The variable 'found' is not empty => "myDirectory"` exists.
fi
DIRECTORY=/tmp
if [ -d "$DIRECTORY" ]; then
echo "Exists"
fi
Try online
Actually, you should use several tools to get a bulletproof approach:
DIR_PATH=`readlink -f "${the_stuff_you_test}"` # Get rid of symlinks and get abs path
if [[ -d "${DIR_PATH}" ]] ; Then # Now you're testing
echo "It's a dir";
fi
There isn't any need to worry about spaces and special characters as long as you use "${}".
Note that [[]] is not as portable as [], but since most people work with modern versions of Bash (since after all, most people don't even work with command line :-p), the benefit is greater than the trouble.
Have you considered just doing whatever you want to do in the if rather than looking before you leap?
I.e., if you want to check for the existence of a directory before you enter it, try just doing this:
if pushd /path/you/want/to/enter; then
# Commands you want to run in this directory
popd
fi
If the path you give to pushd exists, you'll enter it and it'll exit with 0, which means the then portion of the statement will execute. If it doesn't exist, nothing will happen (other than some output saying the directory doesn't exist, which is probably a helpful side-effect anyways for debugging).
It seems better than this, which requires repeating yourself:
if [ -d /path/you/want/to/enter ]; then
pushd /path/you/want/to/enter
# Commands you want to run in this directory
popd
fi
The same thing works with cd, mv, rm, etc... if you try them on files that don't exist, they'll exit with an error and print a message saying it doesn't exist, and your then block will be skipped. If you try them on files that do exist, the command will execute and exit with a status of 0, allowing your then block to execute.
[[ -d "$DIR" && ! -L "$DIR" ]] && echo "It's a directory and not a symbolic link"
N.B: Quoting variables is a good practice.
Explanation:
-d: check if it's a directory
-L: check if it's a symbolic link
To check more than one directory use this code:
if [ -d "$DIRECTORY1" ] && [ -d "$DIRECTORY2" ] then
# Things to do
fi
Check if the directory exists, else make one:
[ -d "$DIRECTORY" ] || mkdir $DIRECTORY
[ -d ~/Desktop/TEMPORAL/ ] && echo "DIRECTORY EXISTS" || echo "DIRECTORY DOES NOT EXIST"
Using the -e check will check for files and this includes directories.
if [ -e ${FILE_PATH_AND_NAME} ]
then
echo "The file or directory exists."
fi
This answer wrapped up as a shell script
Examples
$ is_dir ~
YES
$ is_dir /tmp
YES
$ is_dir ~/bin
YES
$ mkdir '/tmp/test me'
$ is_dir '/tmp/test me'
YES
$ is_dir /asdf/asdf
NO
# Example of calling it in another script
DIR=~/mydata
if [ $(is_dir $DIR) == "NO" ]
then
echo "Folder doesnt exist: $DIR";
exit;
fi
is_dir
function show_help()
{
IT=$(CAT <<EOF
usage: DIR
output: YES or NO, depending on whether or not the directory exists.
)
echo "$IT"
exit
}
if [ "$1" == "help" ]
then
show_help
fi
if [ -z "$1" ]
then
show_help
fi
DIR=$1
if [ -d $DIR ]; then
echo "YES";
exit;
fi
echo "NO";
As per Jonathan's comment:
If you want to create the directory and it does not exist yet, then the simplest technique is to use mkdir -p which creates the directory — and any missing directories up the path — and does not fail if the directory already exists, so you can do it all at once with:
mkdir -p /some/directory/you/want/to/exist || exit 1
if [ -d "$DIRECTORY" ]; then
# Will enter here if $DIRECTORY exists
fi
This is not completely true...
If you want to go to that directory, you also need to have the execute rights on the directory. Maybe you need to have write rights as well.
Therefore:
if [ -d "$DIRECTORY" ] && [ -x "$DIRECTORY" ] ; then
# ... to go to that directory (even if DIRECTORY is a link)
cd $DIRECTORY
pwd
fi
if [ -d "$DIRECTORY" ] && [ -w "$DIRECTORY" ] ; then
# ... to go to that directory and write something there (even if DIRECTORY is a link)
cd $DIRECTORY
touch foobar
fi
In kind of a ternary form,
[ -d "$directory" ] && echo "exist" || echo "not exist"
And with test:
test -d "$directory" && echo "exist" || echo "not exist"
file="foo"
if [[ -e "$file" ]]; then echo "File Exists"; fi;
The ls command in conjunction with -l (long listing) option returns attributes information about files and directories.
In particular the first character of ls -l output it is usually a d or a - (dash). In case of a d the one listed is a directory for sure.
The following command in just one line will tell you if the given ISDIR variable contains a path to a directory or not:
[[ $(ls -ld "$ISDIR" | cut -c1) == 'd' ]] &&
echo "YES, $ISDIR is a directory." ||
echo "Sorry, $ISDIR is not a directory"
Practical usage:
[claudio#nowhere ~]$ ISDIR="$HOME/Music"
[claudio#nowhere ~]$ ls -ld "$ISDIR"
drwxr-xr-x. 2 claudio claudio 4096 Aug 23 00:02 /home/claudio/Music
[claudio#nowhere ~]$ [[ $(ls -ld "$ISDIR" | cut -c1) == 'd' ]] &&
echo "YES, $ISDIR is a directory." ||
echo "Sorry, $ISDIR is not a directory"
YES, /home/claudio/Music is a directory.
[claudio#nowhere ~]$ touch "empty file.txt"
[claudio#nowhere ~]$ ISDIR="$HOME/empty file.txt"
[claudio#nowhere ~]$ [[ $(ls -ld "$ISDIR" | cut -c1) == 'd' ]] &&
echo "YES, $ISDIR is a directory." ||
echo "Sorry, $ISDIR is not a directoy"
Sorry, /home/claudio/empty file.txt is not a directory
There are great solutions out there, but ultimately every script will fail if you're not in the right directory. So code like this:
if [ -d "$LINK_OR_DIR" ]; then
if [ -L "$LINK_OR_DIR" ]; then
# It is a symlink!
# Symbolic link specific commands go here
rm "$LINK_OR_DIR"
else
# It's a directory!
# Directory command goes here
rmdir "$LINK_OR_DIR"
fi
fi
will execute successfully only if at the moment of execution you're in a directory that has a subdirectory that you happen to check for.
I understand the initial question like this: to verify if a directory exists irrespective of the user's position in the file system. So using the command 'find' might do the trick:
dir=" "
echo "Input directory name to search for:"
read dir
find $HOME -name $dir -type d
This solution is good because it allows the use of wildcards, a useful feature when searching for files/directories. The only problem is that, if the searched directory doesn't exist, the 'find' command will print nothing to standard output (not an elegant solution for my taste) and will have nonetheless a zero exit. Maybe someone could improve on this.
The below find can be used,
find . -type d -name dirname -prune -print
One Liner:
[[ -d $Directory ]] && echo true
(1)
[ -d Piyush_Drv1 ] && echo ""Exists"" || echo "Not Exists"
(2)
[ `find . -type d -name Piyush_Drv1 -print | wc -l` -eq 1 ] && echo Exists || echo "Not Exists"
(3)
[[ -d run_dir && ! -L run_dir ]] && echo Exists || echo "Not Exists"
If an issue is found with one of the approaches provided above:
With the ls command; the cases when a directory does not exists - an error message is shown
[[ `ls -ld SAMPLE_DIR| grep ^d | wc -l` -eq 1 ]] && echo exists || not exists
-ksh: not: not found [No such file or directory]
sorry for that odd title. I didn't know how to word it the right way.
I'm trying to write a script to filter my wiki files to those got directories with the same name and the ones without. I'll elaborate further.
here is my file system:
what I need to do is print a list of those files which have directories in their name and another one of those without.
So my ultimate goal is getting:
with dirs:
Docs
Eng
Python
RHEL
To_do_list
articals
without dirs:
orphan.txt
orphan2.txt
orphan3.txt
I managed to get those files with dirs. Here is me code:
getname () {
file=$( basename "$1" )
file2=${file%%.*}
echo $file2
}
for d in Mywiki/* ; do
if [[ -f $d ]]; then
file=$(getname $d)
for x in Mywiki/* ; do
dir=$(getname $x)
if [[ -d $x ]] && [ $dir == $file ]; then
echo $dir
fi
done
fi
done
but stuck with getting those without. if this is the wrong way of doing this please clarify the right one.
any help appreciated. Thanks.
Here's a quick attempt.
for file in Mywiki/*.txt; do
nodir=${file##*/}
test -d "${file%.txt}" && printf "%s\n" "$nodir" >&3 || printf "%s\n" "$nodir"
done >with 3>without
This shamelessly uses standard output for the non-orphans. Maybe more robustly open another separate file descriptor for that.
Also notice how everything needs to be quoted unless you specifically require the shell to do whitespace tokenization and wildcard expansion on the value of a token. Here's the scoop on that.
That may not be the most efficient way of doing it, but you could take all files, remove the extension, and the check if there isn't a directory with that name.
Like this (untested code):
for file in Mywiki/* ; do
if [ -f "$d" ]; then
dirname=$(getname "$d")
if [ ! -d "Mywiki/$dirname" ]; then
echo "$file"
fi
fi
done
To List all the files in current dir
list1=`ls -p | grep -v /`
To List all the files in current dir without extension
list2=`ls -p | grep -v / | sed 's/\.[a-z]*//g'`
To List all the directories in current dir
list3=`ls -d */ | sed -e "s/\///g"`
Now you can get the desired directory listing using intersection of list2 and list3. Intersection of two lists in Bash
I am working on a bash script that I am working on for a universal Linux dotfile install script. I am attempting to get the symlinking working but I have been bashing (no pun intended) my head against the wall trying to figure out why the symlinks will not work and the copying will not work. I currently have this separated into multiple files so I don't have if statements three miles long.
ultimate-install.sh
#! /bin/bash
#
# The ultimate install script for all dotfiles.
if [[ -z "$1" ]]; then
echo "Please specify the directory where all of you dotfiles are located."
exit 1
fi
# Makes sure that the directory does NOT have a trailing slash!
if [[ ${1:(-1)} == "/" ]]; then
DOTFILE_DIR=${1:0:${#1} - 1}
else
DOTFILE_DIR="$1"
fi
# TODO: Clean this mess up and make it more concise.
if [[ -z "$2" ]]; then
if [[ ! -d $HOME/.config/old_dotfiles ]]; then
mkdir "$HOME/.config/old_dotfiles"
fi
BACKUP_DIR="$HOME/.config/old_dotfiles"
else
if [[ -d "$2" ]]; then
BACKUP_DIR="$2"
else
mkdir "$2"
BACKUP_DIR="$2"
fi
fi
read DECISION
if [ $DECISION == "N" -o $DECISION == "n" ]; then
echo "Aborting installation!"
exit
fi
read DECISION
echo
if [ $DECISION == "N" -o $DECISION == "n" ]; then
source src/no-prompts.sh "$DOTFILE_DIR" "$BACKUP_DIR"
else
source src/prompts.sh "$DOTFILE_DIR" "$BACKUP_DIR"
fi
echo "Installation complete. Old dotfiles are backed up to $BACKUP_DIR."
src/no-prompts.sh
#! /bin/bash
#
# Maintained by Daniel Seymour
DOTFILE_DIR="$1"
BACKUP_DIR="$2"
TEST_DIR="/home/daniel/dotfile-test"
function no_prompt_install(){
FILE_NAME="$1"
if [ "${FILE_NAME:0:1}" == "." ]; then
ln -s "$FILE_NAME $TEST_DIR/$FILE_NAME"
else
ln -s ".$FILE_NAME $TEST_DIR/$FILE_NAME"
fi
}
# TODO: implement a check for file type and deal with unknown files.
for FILE in $DOTFILE_DIR/*; do
cp $FILE $BACKUP_DIR
no_prompt_install $FILE
done
src/prompts.sh
#! /bin/bash
#
# Maintained by Daniel Seymour
DOTFILE_DIR="$1"
BACKUP_DIR="$2"
TEST_DIR="/home/daniel/dotfile-test"
function prompt_install {
FILE_PATH=$1
FILE_NAME=${FILE_PATH##*/}
echo "Would you like to install $FILE_NAME? [Y, n]"
read DECISION
if [ $DECISION == "n" -o $DECISION == "N" ]; then
echo "Not installing."
return
else
# TODO: Clean this up into one statement.
if [ ${FILE_NAME:0:1} == "." ]; then
rm -rf "$TEST_DIR/$FILE_NAME"
ln -sn "$FILE_PATH $TEST_DIR/$FILE_NAME"
else
FILE_NAME="."$FILE_NAME
rm -rf "$TEST_DIR/$FILE_NAME"
ln -sn "$FILE_PATH $TEST_DIR/$FILE_NAME"
fi
fi
}
# TODO: implement a check for file type and deal with unknown files.
for FILE in $DOTFILE_DIR/*; do
cp $FILE $BACKUP_DIR
prompt_install $FILE
done
The above is trimmed for long echo statements that do a lot of explaining.
The basic idea of this script is to take as many as two arguments (the dotfile directory to install and if specified, the custom backup directory, $1 and $2 respectively). The script should then copy all of the files in the target directory to BACKUP_DIR and symlink all of the dotfiles in the DOTFILE_DIR to TEST_DIR. (TEST_DIR will be $HOME in the production scripts.) Great in theory, right?
The complication comes when I run the script. None of the files are copied or symlinked as they should be. Instead, I end up with NO copy (probably due to the same issue as the symlink not working) and a broken symlink in the current directory.
One last piece of information. I am executing the file from the directory that contains ultimate-install.sh (/home/daniel/Projects/Git-Repos/Ultimate-Dotfile-Install-Scripts).
So where did I go wrong?
PS Please don't comment on the TODOs. :)
Short answer
Your quoting is wrong.
ln -sn -- "$FILE_PATH" "$TEST_DIR/$FILE_NAME"
Longer answer
This does not really relate to your problem, but I want to point it out.
Do not use "" inside [[ ]], so instead of this if [[ -z "$1" ]]; then use this if [[ -z $1 ]]; then
What is the point of making sure that directory does not have a trailing slash? It has no effect! /usr/bin/ is the same directory as /usr/bin or /usr////bin or /usr////////bin//////
Do not check if a directory exists when creating directories. Use -p option! Example: mkdir -p "$HOME/.config/old_dotfiles"
Instead of if [ $DECISION == "N" -o $DECISION == "n" ]; use if [[ ${DECISION^^} == N]];
I have another great answer about bash code style HERE. Please check it out! Also read the comments, since I was explaining there exactly your issue.
hey so I have some code for the question bellow but I am stuck its not working and I don't really know what I am doing.
This script should remove the contents of the dustbin directory.
If the -a option is used the script should remove ALL files from the dustbin.
Otherwise, the script should display the filenames in the dustbin one by one and ask the user for confirmation that they should be deleted
#!/bin/sh
echo " The files in the dustbin are : "
ls ~/TAM/dustbin
read -p " Please enter -a to delete all files else you will be prompted to delete one by one : " filename
read ans
if ["filename" == "-a"]
cat ~/TAM/dustbin
rm -rf*
else
ls > ~/TAM/dustbin
for line in `cat ~/TAM/dustbin`
do
echo "Do you want to delete this file" $line
echo "Y/N"
read ans
case "ans" in
Y) rm $line ;;
N) "" ;;
esac
EDITED VERSION
if test ! -f ~/TAM/dustbin/*
then
echo "this directory is empty"
else
for resfile in ~/TAM/dustbin/*
do
if test -f $resfile ; then
echo "Do you want to delete $resfile"
echo "Y/N"
read ans
if test $ans = Y ; then
rm $resfile
echo "File $resfile was deleted"
fi
fi
done
fi
this works however Now I get one of 2 errors either
line 4 requires a binary operator or line 4: to many arguments
I see one obvious mistake:
rm -rf*
when it should be
rm -rf *
to be asked about every file deletion - add -i key
rm -rfi *
Many problems here:
A space missing before the * in rm. The space is needed so the shell can recognize the wildcard and expand it.
Do you really want to remove all the files in the current directory? If not, specify the path rm -rf /path/to/files/* or cd into the directory, preferably with cd /path/to/files || exit 1.
I do not understand the logic of the script. You show a dustbin, but if the user gives -a, you overwrite it with all the non-hidden files (ls > dustbin). Is that what you want?
First of all, case "ans" of just matches a string "ans" to other strings, which is obviously false, you need case $ans of to get the value of variable ans. if ["filename" == "-a"] is also comparison between two strings, which is always false. The first parameter of a script can be accessed as $1 (the second as $2 and so on).
Please read man 1 sh to get the basics of shell programming (all of the above notes can be found there).