This question already has answers here:
When to wrap quotes around a shell variable?
(5 answers)
Closed 1 year ago.
I'm new to bash and I am trying to create a script that should find an archive in a given directory. $1 is the name of archive.
When the given path is ./1/ar.tgz the script works. But when path is ../data 1/01_text.tgz I have the following problem:
dirname: extra operand "1/01_text.tgz"
and then No such file or directory.
Here is my code fragment:
VAR=$1
DIR=$(dirname ${VAR})
cd $DIR
What am I doing wrong?
Ahmed's answer is right, but you also need to enclose VAR in double quotes. The correct code fragment is:
VAR=$1
DIR=$(dirname "$VAR")
cd "$DIR"
The space is causing the problem: cd $DIR gets expanded to cd ../data 1/01_text.tgz and cd doesn't know what to make of the third "argument". Add quotes around the directory: cd "$DIR".
Related
This question already has an answer here:
In bash, how do I expand a wildcard while it's inside double quotes?
(1 answer)
Closed 2 years ago.
I want to write a simple script that does something for every file in user-defined directory. Here's a script that works for predefined directory:
for file in mydir/*; do
printf "$file"
done
Here's similar script that prints name of each file in the directory defined by variable:
for file in "$nicedir*"; do
printf "$file"
done
This second script don't work. Of course, I remembered about slash at the end of the path. (I passed ./ as the argument instead of just .)
Pathname expansion doesn't happen in quoted strings. Keep the wildcard outside of the quotes:
for file in "$nicedir"* ; do
printf '%s\n' "$file"
done
The final slash is usually not required in paths, so you'll more often see
for file in "$nicedir/"*
# or equivalent
for file in "$nicedir"/*
This question already has answers here:
How do I know the script file name in a Bash script?
(25 answers)
Closed 2 years ago.
I want to save a copy of the bash file each time I run it. It should be saved to the output dictionary.
I am doing it like this in the mytrainrtest.sh file:
mkdir -p "${EXP_DIR}/train"
cp "${WORK_DIR}"/mytrainrtest.sh "${EXP_DIR}"/.
Now I have much more bash files with name my****** as copies of the upper one, each with different names.
How can I write the line, so the bash file will recognize its name to copy itself?
Use the $0 special variable which contains the name of the currently executing script.
cp "$0" "$exp_dir"/
Script name(path) stored in a special var $0
#!/bin/bash
echo $0
$ ./test
./test
This question already has answers here:
Do not show results if directory is empty using Bash
(3 answers)
Closed 4 years ago.
So I have to find all the files in the directory that start with the letter a, and list them out. This is pretty easy by doing
cd some_directory
for file in a*; do
echo "$file"
done
However I want that if there are no files present that match a*, then the for loop will not run at all. Currently, if this is the case then the shell will echo
a*
Is there a way to do this? Thank you
Your text is opposite of your title, in my answer below I've assumed the text is your intention and your title is incorrect:
globs can be made to act like this with the bash shell option "nullglob":
shopt -s nullglob
An alternative is to use find and ignore errors by piping stderr to /dev/null
for file in $(find a* 2>/dev/null); do
echo "$file"
done
This question already has answers here:
I just assigned a variable, but echo $variable shows something else
(7 answers)
Closed 4 years ago.
My directory structure is /local/mnt/abcd/sub 1
So inside the 'sub 1' folder, I am trying to execute the following script
SOURCEDIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
readlink -f $SOURCEDIR/..
it gives output as : /local/mnt/abcd/sub not /local/mnt/abcd/sub\ 1
Basically, it is not able to handle if there is a space present in the folder name. So I want to know is there any alternative to readlink or any other way we can get the absolute path
You need to quote the parameter expansion so that readlink gets the path as a single argument.
readlink -f "$SOURCEDIR/.."
Without the quotes, it's equivalent to
readlink -f /local/mnt/abcd/sub 1/..
Put double-quotes round the argument to keep it as a single argument:
readlink -f "$SOURCEDIR/.."
This question already has answers here:
Rename multiple files in shell [duplicate]
(4 answers)
Closed 4 years ago.
I've got a small problem with my bash script. I try to change file name in current directory for whole files with txt extension to text extension. For exampel 1.txt to 1.text
My script looks like this now:
#!/bin/bash
FILES=`ls /home/name/*.txt`
NAME=*.txt
RENAME=*.text
for file in FILES
do
mv $NAME $RENAME
done
i try whole combination with single, double quotes and backticks and I receive errors all the time.
Do you have some ideas how to receive wildcards "*" in bash?
Thanks.
That's not at all how you do that.
#!/bin/bash
shopt -s nullglob
OLD=.txt
NEW=.text
FILES=(/home/name/*"$OLD")
for file in "${FILES[#]}"
do
mv "$file" "${file%$OLD}$NEW}"
done
There are a number of issues with your script. Firstly, you shouldn't run ls and attempt to store its output like that. If you want to iterate through those file, just do it in the loop:
for file in /home/name/*.txt
Now the shell is doing all the work for you, and as a bonus handling any kind of weird filenames that you might have.
In your example you were looping over the literal string "FILES", not the variable, but I guess that was just a typo.
The built-in way to change the filename is to use a parameter expansion to remove the old one, then concatenate with the new one:
old=txt
new=text
for file in /home/name/*"$old"
do
mv "$file" "${file%$old}$new"
done
If it is possible that there are no files matching the glob, then by default, the /home/name/*.txt will not be expanded and your loop will just run once. then you have a couple of options:
use shopt -s nullglob so that /home/name/*.txt expands to null, and the loop is skipped
add an explicit check inside the loop to ensure that $file exists before trying to mv:
for file in /home/name/*"$old"
do
[ -e "$file" ] || continue
mv "$file" "${file%$old}$new"
done
You can use rename to rename filenames.
rename .txt .text /home/name/*.txt
And if you want to do this by looping, you can
for FILE in /data/tmp/*.txt; do
mv "${FILE}" "${FILE/.txt/.text}"
done