Every time I run this code I get the error File or directory doesn't exist. Why?
read -p "Enter the filename/path of the file you wish to delete : " filename
echo "Do you want to delete this file"
echo "Y/N"
read ans
case "$ans" in
Y) "`readlink -f $filename`" >>~/TAM/store & mv $filename ~/TAM/dustbin
echo "File moved" ;;
N) "File Not deleted" ;;
esac
When I enter the file name/directory exactly and triple check its right I still get this error, but the readlink part works.
Paraphrasing/summarizing/extending my answer for a similar question:
I doubt you really meant to use & instead of && in your script.
"File Not deleted" is not a valid command on any Linux system that I have used. Perhaps you are missing an echo there?
You have to fix your variable quotation. If the filename variable contains whitespace, then $filename is expanded by the shell into more than one arguments. You need to enclose it into double quotes:
mv "$filename" ~/TAM/dustbin
I do not see your script creating the ~/TAM/ directory anywhere...
You are missing an echo and one &&.
Use echo "`command`" to pipe the result string of commands. Alternatively, you may directly use the command without backticks and quotes, (not storing the result in a string), in which case you do not need an echo because the command will pipe its result to the next command.
The single & will run the preceding command in the background (async.). To check for return values and conditionally execute you need && and ||.
Here is a complete solution/example (incl. some more logging):
# modified example not messing the $HOME dir.
# should be save to run in a separate dir
touch testfile #create file for testing
read -p "Enter the filename/path of the file you wish to delete : " filename
echo "Do you want to delete this file: $filename"
echo "Y/N"
read ans
touch movedfiles #create a file to store the moved files
[ -d _trash ] || mkdir _trash #create a dustbin if not already there
case "$ans" in
Y) readlink -f "$filename" >> movedfiles && echo "File name stored" &&
mv "$filename" _trash && echo "File moved" ;;
N) echo "File Not deleted" ;;
esac
cat movedfiles #display all moved files
Related
I want to remove the extension of specific files with a given extension.
So for instance, in a directory foobar, we have foo.txt, bar.txt foobar.jpg.
Additionally, the extension that I've put in to be removed is txt
After calling the program, my output should be foo bar foobar.jpg
Here is my code so far:
#!/bin/bash
echo "Enter an extension"
read extension
echo "Enter a directory"
read directory
for file in "$directory"/*; do //
if [[ $file == *.txt ]]
then
echo "${file%.*}"
else
echo "$file"
fi
done
However when I run this on a given directory, nothing shows up.
I'm assuming that there is a problem with how I referred to the directory ( in the line where I placed a //) and I've tried to research on how to solve it but to no avail.
What am I doing wrong?
If files do exist in a valid directory you've entered then they should show up — with one exception. If you are using ~/ (shorthand home directory) then it will be treated as plain text in your for loop. The read variable should be substituted into another variable so the for loop can treat it as a directory (absolute paths should work normally as well).
#!/bin/bash
echo "Enter an extension"
read -r extension
echo "Enter a directory"
read -r directory
dir="${directory/#\~/$HOME}"
for file in "$dir"/*; do
if [[ $file == *."$extension" ]]
then
echo "${file%.*}"
else
echo "$file"
fi
done
You can simplify your for-loop:
for file in "$directory"/*; do
echo "${f%.$extension}";
done
The % instructions removes only matching characters. If nothing matches, the original string (here f) is returned.
When you write bash scripts it's more common to pass arguments to your script via command line arguments rather than by reading it from standard input via read program.
Passing arguments via command line:
#!/bin/bash
# $# - a bash variable which holds a number of arguments passed
# to script via command line arguments
# $0 holds the name of the script
if [[ $# -ne 2 ]]; then # checks if exactly 2 arguments were passed to script
echo "Usage: $0 EXTENSION DIRECTORY"
exit -1;
fi
echo $1; # first argument passed to script
echo $2; # second arugment passed to script
This approach is more efficient because a subprocess is spawn for read command to run and there is no subprocess spawn for reading command line arguments.
There is no need to manually loop through directory, you can use find command to find all files with given extension within given directory.
find /path/to/my/dir -name '*.txt'
find $DIRECTORY -name "*.$EXTENSION"
# note that single quotes in this context would prevent $EXTENSION
# variable to be resolved, so double quotes are used " "
# find searches for files inside $DIRECTORY and searches for files
# matching pattern '*.$EXTENSION'
Note that to avoid bash filename expansion sometimes it is required to wrap actual pattern in single quotes ' ' or double quotes " ". See Bash Filename Expansion
So now your script can look like this:
#!/bin/bash
if [[ $# -ne 2 ]]; then
echo "Usage: $0 EXTENSION DIRECTORY"
exit -1;
fi
$EXTENSION = $1 # for better readability
$DIRECTORY = $2
for file in `find $DIRECTORY -name "*.$EXTENSION"`; do
mv $file ${file%.$EXTENSION}
done
Construct ${file%.$EXTENSION} is called Shell Parameter Expansion it searches for occurrence of .$EXTENSION inside file variable and deletes it.
Notice that in the script it is easy to pass extension as directory and vice versa.
We can check if second argument is in fact directory, we can use following construction:
if ! [[ -d $DIRECTORY ]]; then
echo $DIRECTORY is not a dir
exit -1
fi
This way we can exit from the script earlier with more readable error.
To sum up entire script could look like this:
#!/bin/bash
if [[ $# -ne 2 ]]; then
echo "Usage: $0 EXTENSION DIRECTORY"
exit -1;
fi
EXTENSION=$1 # for better readability
DIRECTORY=$2
if ! [[ -d $DIRECTORY ]]; then
echo $DIRECTORY is not a directory.
exit -1
fi
for file in `find $DIRECTORY -name "*.$EXTENSION"`; do
mv $file ${file%.$EXTENSION}
done
Example usage:
$ ./my-script.sh txt /path/to/directory/with/files
im writing a script that allows the user to create a backup of a file they choose by allowing them to input the file name. the file will then have backup followed by being date stamped at the end of it's name and saved on the home drive. but whenever i try to run it i get an error: cp: missing destination file operand after '_backup_2017_12_16'
here's my code:
title="my script 3"
prompt="Enter:"
options=("create a backup of a file")
echo "$title"
PS3="$prompt "
select opt in "${options[#]}" "Quit"; do
case "$REPLY" in
esac
cp "$filename""${file}_backup_$(date +%Y_%m_%d)"
done
Your case statement is currently empty. You need it to handle your chosen option
There needs to be a space between arguments: cp source dest
If you are using array for the options, you can also put Quit in there
If you choose the option to create a backup, you need to prompt the user to enter a filename. read command is used to get user input
Putting it all together, your script could look like this:
#!/usr/bin/env bash
options=("Backup" "Quit")
prompt="Enter: "
title="My script 3"
echo "$title"
PS3=$prompt
select opt in "${options[#]}"; do
case $opt in
"Backup")
IFS= read -r -p "Enter filename: " filename
cp -- "$filename" "${filename}_backup_$(date +%Y_%m_%d)" && echo "Backup created..."
;;
"Quit") break ;;
*) echo "Wrong option..." ;;
esac
done
I'm currently trying to use the following linux script to loop through folders and perform calculations using a function:
for f in s*
do
echo "You are in the following folder - $s"
cd $s
# FUNCTION SHOULD BE HERE
cd /C/Users/Eric/Desktop/Files
done
The problem: How can I use the foldername to find the correct file? For example, the foldername is scan1 and I want to use the file called gaf_scan1_recording_mic.nii for the function.
Thanks a lot,
Eric
In most cases, $var and ${var} are the same (the braces are only needed for ambiguity in the expressions):
var=test
echo $var
# test
echo ${var}
# test
echo $varworks
# prints nothing (there is no variable 'varworks')
echo ${var}works
# testworks
You can use the folder name like this (gaf_${f}_recording_mic.nii):
for f in *; do
# Check if $f is a directory
if [[ -d $f ]]; then
echo "You are in the following folder - $f"
cd $f
# The filename to use for your function
do_stuff gaf_${f}_recording_mic.nii
fi
done
How to write a bash shell script called 'abc' which takes one argument, the name of a directory, and adds the extension ".xyz" to all visible files in the directory that don't already have it
I have mostly written the code which changes the filenames inside the current directory but I can't get the script to accept an argument (directory name) and change the filenames of that directory
#!/bin/bash
case $# in
0) echo "No directory name provided" >&2 ; exit 1;;
1) cd "${1}" || exit $?;;
*) echo "Too many parameters provided" >&2 ; exit 1;;
esac
for filename in *
do
echo $filename | grep "\.xyz$"
if [ "$?" -ne "0" ]
then mv "$filename" "$filename.old"
fi
done
additional instructions include;
Within 'abc', use a "for" control structure to loop through all the non-hidden filenames
in the directory name in $1. Also, use command substitution
with "ls $1" instead of an ambiguous filename, or you'll descend into subdirectories.
EDIT: The top part of the question has been answered below, however the second part requires me to modify my own code according to the following instructions:
Modify the command substitution that's being used to create the loop values that will be placed into the "filename" variable. Instead of just an "ls $1", pipe the output into a "grep". The "grep" will search for all filenames that DO NOT end in ".xyz". This can easily be done with the "grep -v" option. With this approach, you can get rid of the "echo ... | grep ..." and the "if" control structure inside the loop, and simply do the rename.
How would I go about achieving this because according to my understanding, the answer below is already only searching through filenames without the .xyz extension however it is not being accepted.
Your description is a little unclear in places, so I've gone with the most obvious:
#!/bin/bash
# validate input parameters
case $# in
0) echo "No directory name provided" >&2 ; exit 1;;
1) cd "${1}" || exit $?;;
*) echo "Too many parameters provided" >&2 ; exit 1;;
esac
shopt -s extglob # Enables extended globbing
# Search for files that do not end with .xyz and rename them (needs extended globbing for 'not match')
for filename in !(*.xyz)
do
test -f && mv "${filename}" "${filename}.xyz"
done
The answer to the second part is this:
#!/bin/bash
for file in $(ls -1 "$1" | grep -v '\.old$'); do
mv "$file" "$file.old"
done
I got it from somewhere
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).