New to shell scripting and I want to test to see if the variables I created are valid directories and if not send the user into a while loop to enter the directory and only allow exit when a valid directory is entered.
So far this is what my script looks like:
~/bin/bash
source_dir="$1"
dest_dir="$2"
mkdir /#HOME/$source_dir
mkdir /#HOME$dest_dir
if [ -d "$source_dir" ]
then
echo "$source_dir is a valid directory"
fi
while [[ ! -d "$source_dir" ]]
do
echo "Please enter a valid directory"
read source_dir
done
Is there any way to combine these into a single statement?
The while code will never execute if the directory is valid. Therefore just move the echo "$source_dir is a valid directory" after the loop:
#!/bin/bash
source_dir="$1"
dest_dir="$2"
mkdir "$HOME/$source_dir"
mkdir "$HOME/$dest_dir"
until [[ -d "$source_dir" ]]
do
read -p "Please enter a valid directory" source_dir
done
echo "$source_dir is a valid directory"
Notes:
a few code typos were fixed, e.g. /#HOME$dest_dir should be "$HOME/$dest_dir".
any while ! can be shortened to until.
The above code lacks a few things:
It tries create a new dir, then if that fails, has the user enter an already existing directory. It might be better to let the user create a new directory, but only if it doesn't already exist.
It would be better to check if $dest_dir exists.
Here's a more thorough approach using a shell function:
#!/bin/bash
untilmkdir ()
{
d="$1";
until mkdir "$d" ; do
read -p "Please enter a valid directory: " d
[ -d "$d" ] && break
done;
echo "$d is a valid directory" 1>&2
echo "$d"
}
source_dir=$(untilmkdir "$HOME/$1")
dest_dir=$(untilmkdir "$HOME/$2")
Notes:
The prompts in untilmkdir are printed to stderr.
The name of whatever directory untilmkdir creates is printed to stdout.
Having untilmkdir print to both stderr and stdout allows storing the successfully created name to a variable.
Related
How do I test a directory in a while loop where if the directory doesn't exist, then it does the following blank things. I'm trying to prompt the user for input when the directory doesn't exist so the user can retry. Once they get it right, then the script exits.
My script has an infinite loop and I don't know how to fix it. Here is what my bash script looks like:
#!/bin/bash
source_dir=$1
dest_dir=$2
while [[ ! -d "$source_dir" ]]
do
echo "This is not a directory. Enter the source directory: "
read "$source_dir"
done
while [[ ! -d "$dest_dir" ]]
do
echo "This is not a directory. enter the destination directory: "
read "$dest_dir"
done
Certainly,
read "$source_dir"
does not make sense. To understand this, assume that your script is called with the parameter FOO. Hence, you first set source_dir to FOO, and the test [[ -d $source_dir ]] will do a [[ -d FOO ]] and the directory FOO does not exist. Therefore you perform your read command, which will parameter-expand into read FOO. This means to read one line from STDIN and store it into the variable FOO.
If you want to change the value of the variable source_dir, you have to do a
read source_dir
I want to enter the name of a directory and check if it exists.
If it doesn't exist I want to create but I get the error mkdir: cannot create directory'./' File exists
My code says that the file exists even though it doesn't. What am I doing wrong?
echo "Enter directory name"
read dirname
if [[ ! -d "$dirname" ]]
then
if [ -L $dirname]
then
echo "File doesn't exist. Creating now"
mkdir ./$dirname
echo "File created"
else
echo "File exists"
fi
fi
if [ -L $dirname]
Look at the error message produced by this line: “[: missing `]'” or some such (depending on which shell you're using). You need a space inside the brackets. You also need double quotes around the variable expansion unless you use double brackets; you can either learn the rules, or use a simple rule: always use double quotes around variable substitution and command substitution — "$foo", "$(foo)".
if [ -L "$dirname" ]
Then there's a logic error: you're creating the directory only if there is a symbolic link which does not point to a directory. You presumably meant to have a negation in there.
Don't forget that the directory might be created while your script is running, so it's possible that your check will show that the directory doesn't exist but the directory will exist when you try to create it. Never do “check then do”, always do “do and catch failure”.
The right way to create a directory if it doesn't exist is
mkdir -p -- "$dirname"
(The double quotes in case $dirname contains whitespace or globbing characters, the -- in case it starts with -.)
Try this code:
echo "Enter directory name"
read dirname
if [ ! -d "$dirname" ]
then
echo "File doesn't exist. Creating now"
mkdir ./$dirname
echo "File created"
else
echo "File exists"
fi
Output Log:
Chitta:~/cpp/shell$ ls
dir.sh
Chitta:~/cpp/shell$ sh dir.sh
Enter directory name
New1
File doesn't exist. Creating now
File created
chitta:~/cpp/shell$ ls
New1 dir.sh
Chitta:~/cpp/shell$ sh dir.sh
Enter directory name
New1
File exists
Chitta:~/cpp/shell$ sh dir.sh
Enter directory name
New2
File doesn't exist. Creating now
File created
Chitta:~/cpp/shell$ ls
New1 New2 dir.sh
try this: ls yourdir 2>/dev/null||mkdir yourdir, which is tiny and concise and fulfils your task.
read -p "Enter Directory Name: " dirname
if [[ ! -d "$dirname" ]]
then
if [[ ! -L $dirname ]]
then
echo "Directory doesn't exist. Creating now"
mkdir $dirname
echo "Directory created"
else
echo "Directory exists"
fi
fi
I'm trying to compile a script that will read user input, and check if the file after the y/n statement. Then it will make files executable. I think the problem with my script is conditional ordering but check it out yourself:
target=/home/user/bin/
cd $target
read -p "This will make the command executable. Are you sure? (y/n)" CONT
if [ "$CONT" == "y" ];
then
chmod +x $1
echo "File $1 is now executable."
else
if [ "$(ls -A /home/user/bin/)" ];
then
echo "File not found."
else
echo "Terminating..."
fi
fi
As I said, I need the script to scan for the file after the y/n statement is printed. The script works fine how it is but still gives the "file is now executable" even if the argument file doesn't exist (but just gives the standard system "cannot find file" message after the echo'd text).
Your script is mostly correct, you just need to check if the file exists first. Also, it's not the best practice to use cd in shell scripts and not needed here.
So re-writing it
#!/bin/bash
target="/home/user/bin/$1"
if [[ ! -f $target ]]; then
echo "File not found."
else
read -p "This will make the command executable. Are you sure? (y/n) " CONT
if [[ $CONT == "y" ]]; then
chmod +x "$target"
echo "File $1 is now executable."
else
echo "Terminating..."
fi
fi
To get an understanding:
Your script will take one argument (a name of a file).
You ask if you want to make that file executable.
If the answer is 'yes', you make the file executable.
Otherwise, you don't.
You want to verify that the file exists too?
I'm trying to understand your logic. What does this:
if [ "$(ls -A /home/user/bin/)" ];
suppose to do. The [ ... ] syntax is a test. And, it has to be one of the valid tests you see here. For example, There's a test:
-e file: True if file exists.
That mean, I can see if your file is under /home/user/bin:
target="/home/user/bin"
if [ -e "$target/$file" ] # The "-e" test for existence
then
echo "Hey! $file exists in the $target directory. I can make it executable."
else
echo "Sorry, $file is not in the $target directory. Can't touch it."
fi
Your $(ls -A /home/user/bin/) will produce a file listing. It's not a valid test like -e unless it just so happens that the first file in your listing is something like -e or -d.
Try to clarify what you want to do. I think this is something more along the lines you want:
#! /bin/bash
target="/home/user/bin"
if [ -z "$1" ] # Did the user give you a parameter
then
echo "No file name given"
exit 2
fi
# File given, see if it exists in $target directory
if [ ! -e "$target/$1" ]
then
echo "File '$target/$1' does not exist."
exit 2
fi
# File was given and exists in the $target directory
read -p"Do you want $target/$1 to be executable? (y/n)" continue
if [ "y" = "$continue" ]
then
chmod +x "$target/$1"
fi
Note how I'm using the testing, and if the testing fails, I simply exit the program. This way, I don't have to keep embedding if/then statements in if/then statements.
This question already has answers here:
How do I prompt for Yes/No/Cancel input in a Linux shell script?
(37 answers)
Closed 3 years ago.
I'm currently learning Unix and have come across a question in a book that I'm trying to solve.
I'm trying to write a script that asks a user to enter a file name.
Then, the script needs to check for file existence. If the file does not exist, that script should display an error message and then exit the script.
If the file exists, the script should ask if the user wants to delete the file:
If the answer is yes or y, the script should remove the file.
If the answer is no or n, the script should exit from the script.
If the answer is neither yes nor no, the script should display an error message and exit from the script.
This what I have written so far but have come across with a few errors:
#!/bin/bash
file=$1
if [ -f $file ];
then
echo read -p "File $file existes,do you want to delete y/n" delete
case $delete in
n)
exit
y) rm $file echo "file deleted";;
else
echo "fie $file does not exist"
exit
fi
If anyone come explain where I have gone wrong it would be greatly appreciated
I'd suggest this form:
#!/bin/bash
file=$1
if [[ -f $file ]]; then
read -p "File $file exists. Do you want to delete? [y/n] " delete
if [[ $delete == [yY] ]]; then ## Only delete the file if y or Y is pressed. Any other key would cancel it. It's safer this way.
rm "$file" && echo "File deleted." ## Only echo "File deleted." if it was actually deleted and no error has happened. rm probably would send its own error info if it fails.
fi
else
echo "File $file does not exist."
fi
Also you can add -n option to your prompt to just accept one key and no longer require the enter key:
read -n1 -p "File $file exists. Do you want to delete? [y/n] " delete
You added echo before read and I removed it.
In it's simplest form, you could do the following:
$ rm -vi file
To give you an example:
$ mkdir testdir; touch testdir/foo; cd testdir; ls
foo
$ rm -vi bar
rm: cannot remove 'bar': No such file or directory
$ rm -vi foo
rm: remove regular empty file 'foo'? y
removed 'foo'
I am writing a simple script to check if an entered directory path exists. This is what I have
echo "Please specify complete directory path"
read file_path
for file in $file_path; do
if [[ -d "$file" ]]; then
echo "$file is a directory"
break
else
echo "$file is not a directory, please try again."
fi
done
What I need is if it is not a directory to go back and ask for the file path again.
Thanks.
How about this?
echo "Please specify complete directory path"
while read file; do
if [[ -d "$file" ]]; then
echo "$file is a directory"
break
fi
echo "$file is not a directory, please try again."
done
No need to split the path into its parts, testing the entire path with -d will tell you whether or not it is a directory. You need to put the entire test into a while loop until the user gets it right:
#/bin/sh
set -e
file_path=''
while [ ! -d "$file_path" ]
do
echo "Please specify complete directory path"
read file_path
if [ ! -d "$file_path" ]
then
echo "$file_path is not a directory, please try again."
fi
done
I can use it like this
$ sh /tmp/test.sh
Please specify complete directory path
foobar
foobar is not a directory, please try again.
Please specify complete directory path
/var/www