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
Related
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.
I'm creating a very simple bash script that will check to see if the directory exists, and if it doesn't, create one.
However, no matter what directory I put in it doesn't find it!
Please tell me what I'm doing wrong.
Here is my script.
#!/bin/bash
$1="/media/student/System"
if [ ! -d $1 ]
then
mkdir $1
fi
Here is the command line error:
./test1.sh: line 2: =/media/student/System: No such file or directory
Try this
#!/bin/bash
directory="/media/student/System"
if [ ! -d "${directory}" ]
then
mkdir "${directory}"
fi
or even shorter with the parent argument of mkdir (manpage of mkdir)
#!/bin/bash
directory="/media/student/System"
mkdir -p "${directory}"
In bash you are not allow to start a variable with a number or a symbol except for an underscore _. In your code you used $1 , what you did there was trying to assign "/media/student/System" to $1, i think maybe you misunderstood how arguments in bash work. I think this is what you want
#!/bin/bash
directory="$1" # you have to quote to avoid white space splitting
if [[ ! -d "${directory}" ]];then
mkdir "$directory"
fi
run the script like this
$ chmod +x create_dir.sh
$ ./create_dir.sh "/media/student/System"
What the piece of code does is to check if the "/media/student/System" is a directory, if it is not a directory it creates the directory
I have checked everywhere and tried many different "Solutions" on checking to see if the directory exists. Here's my code:
#!/bin/bash
echo -e "Where is the directory/file located?"
read $DIRECTORY
if [ -d "$DIRECTORY" ]; then
echo "Exists!"
else
echo "Does not exist!"
fi
What I am trying to do is have the user input a directory and for the script to check if it exists or not and return a result. This will ultimately tar/untar a directory. Regardless of whether the directory exists or not, it returns the answer "Does not exist!". (The input i'm trying is ~/Desktop, and from what I know that is 100% correct. Any concise answers are much appreciated :).
Your script can be refactored to this:
#!/bin/bash
read -p 'Where is the directory/file located?' dir
[[ -d "$dir" ]] && echo 'Exists!' || echo 'Does not exist!'
Basically use read var instead of read $var
Better not to use all caps variable names in BASH/shell
Use single quotes while using ! in BASH since it denotes a history event
I made this script that should receive one or more parameter, and those parameter are all directories, and it has to browse those directories (one by one) and do some operations.
The operations work fine if the parameter is 1 (only one directory),
How should I modify my script to make it works if more than 1 parameter is passed
Example if I want it to do the same operations in 2 or 3 directories at the same time?
Thanks
#!/bin/sh
cd $1
for file in ./* # */
do
if [[ -d $file ]]
then
ext=dir
else
ext="${file##*.}"
fi
mv "${file}" "${file}.$ext"
done
First, if you are using bash use bash shebang (#! /bin/bash).
Then use
#! /bin/bash
for d in "$#"
do
echo "Do something with $d"
done
to iterate over the command line arguments (dirs in your case)
#!/bin/sh
for dir in "$#"; do
for file in "$dir"/*; do
echo "Doing something with '$file'"
done
done
Is it possible to save last entered value of a variable by the user in the bash script itself so that I reuse value the next time while executing again?.
Eg:
#!/bin/bash
if [ -d "/opt/test" ]; then
echo "Enter path:"
read path
p=$path
else
.....
........
fi
The above script is just a sample example I wanted to give(which may be wrong), is it possible if I want to save the value of p permanently in the script itself to so that I use it somewhere later in the script even when the script is re-executed?.
EDIT:
I am already using sed to overwrite the lines in the script while executing, this method works but this is not at all good practice as said. Replacing the lines in the same file as said in the below answer is much better than what I am using like the one below:
...
....
PATH=""; #This is line no 7
DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )";
name="$(basename "$(test -L "$0" && readlink "$0" || echo "$0")")";
...
if [ condition ]
fi
path=$path
sed -i '7s|.*|PATH='$path';|' $DIR/$name;
Someting like this should do the asked stuff :
#!/bin/bash
ENTERED_PATH=""
if [ "$ENTERED_PATH" = "" ]; then
echo "Enter path"
read path
ENTERED_PATH=$path
sed -i 's/ENTERED_PATH=""/ENTERED_PATH='$path'/g' $0
fi
This script will ask user a path only if not previously ENTERED_PATH were defined, and store it directly into the current file with the sed line.
Maybe a safer way to do this, would be to write a config file somewhere with the data you want to save and source it . data.saved at the begining of your script.
In the script itself? Yes with sed but it's not advisable.
#!/bin/bash
test='0'
echo "test currently is: $test";
test=`expr $test + 1`
echo "changing test to: $test"
sed -i "s/test='[0-9]*'/test='$test'/" $0
Preferable method:
Try saving the value in a seperate file you can easily do a
myvar=`cat varfile.txt`
And whatever was in the file is not in your variable.
I would suggest using the /tmp/ dir to store the file in.
Another option would be to save the value as an extended attribute attached to the script file. This has many of the same problems as editing the script's contents (permissions issues, weird for multiple users, etc) plus a few of its own (not supported on all filesystems...), but IMHO it's not quite as ugly as rewriting the script itself (a config file really is a better option).
I don't use Linux, but I think the relevant commands would be something like this:
path="$(getfattr --only-values -n "user.saved_path" "${BASH_SOURCE[0]}")"
if [[ -z "$path" ]]; then
read -p "Enter path:" path
setfattr -n "user.saved_path" -v "$path" "${BASH_SOURCE[0]}"
fi