I'm moving some files around, and I want to make sure that the mv command I've typed is correct before I go ahead and run it.

If I was using apt-get, I could use the -s flag to perform a simulation that would actually do anything.

Does mv have a similar function, that would simulate the moving of the files but not actually do anything?

7

4 Answers

Function below is for verbosely checking mv syntax. Note , that it only works for 2 arguments, SOURCE and DESTINATION, and doesn't check for -t flag.

The function is to be placed into ~/.bashrc . To use it immediately , open new terminal or run source ~/.bashrc

mv_check()
{ # Function for checking syntax of mv command # sort of verbose dry run # NOTE !!! this doesn't support the -t flag # maybe it will in future (?) # check number of arguments if [ $# -ne 2 ]; then echo "<<< ERROR: must have 2 arguments , but $# given " return 1 fi # check if source item exist if ! readlink -e "$1" > /dev/null then echo "<<< ERROR: " "$item" " doesn't exist" return 1 fi # check where file goes if [ -d "$2" ] then echo "Moving " "$1" " into " "$2" " directory" else echo "Renaming " "$1" " to " "$2" fi
}

Here's some test runs:

$> mv_check TEST_FILE1 bin/python
Moving TEST_FILE1 into bin/python directory
$> mv_check TEST_FILE1 TEST_FILE2
Renaming TEST_FILE1 to TEST_FILE2
$> mv_check TEST_FILE1 TEST_FILE 2
<<< ERROR: must have 2 arguments , but 3 given
$> mv_check TEST_FILE1 TEST_FILE\ 2
Renaming TEST_FILE1 to TEST_FILE 2
$> mv_check TEST_FILE1 "TEST_FILE 2"
Renaming TEST_FILE1 to TEST_FILE 2
$> mv_check TEST_FILE1
<<< ERROR: must have 2 arguments , but 1 given 

1

There is a programm on github called maybe which may be what you are looking for.

According to their project description, maybe

... allows you to run a command and see what it does to your files without actually doing it! After reviewing the operations listed, you can then decide whether you really want these things to happen or not.

So it will also show you what other programs will do to your files, not only mv.

maybe needs Python to run, but that should not be a problem. It is easy to install or build it using Python's package manager pip.

The installation process and the usage of the program are both described on the project's homepage. Unfortunatly I have no access to a Linux System at the moment, so I can not provide you with any examples on the program's usage.

3

This script should do the trick. It can handle multiple source files/directories, too. Use it the same way you would use mv - mvsim source... dest. Note that it does not pay attention to options, nor does it filter them out (it just treats them as filenames) and it might not work well with symlinks.

#!/bin/bash
if [ $# -lt 2 ]; then echo "Too few arguments given; at least 2 arguments are needed." exit 1
fi
lastArg="${@:$#}"
i=1
for param in "$@"; do if [ ! -e "$param" -a $i -lt $# ]; then echo "Error: $param does not exist." exit 1 elif [ "$param" = "$lastArg" -a $i -lt $# ]; then echo "Error: $param is the same file/directory as the destination." exit 1 fi ((i++))
done
if [ $# -eq 2 ]; then # special case for 2 arguments to make output look better if [ -d "$1" ]; then if [ -d "$2" ]; then echo "Moves directory $1 (and anything inside it) into directory $2" exit 0 elif [ ! -e "$2" ]; then echo "Renames directory $1 to $2" exit 0 else echo "Error: $2 is not a directory; mv cannot overwrite a non-directory with a directory." exit 1 fi else if [ -d "$2" ]; then echo "Moves file $1 into directory $2" elif [ -e "$2" ]; then echo "Renames file $1 to $2, replacing file $2" else echo "Renames file $1 to $2" fi exit 0 fi
elif [ ! -e "$lastArg" ]; then echo "Error: $lastArg does not exist." exit 1
elif [ ! -d "$lastArg" ]; then echo "Error: $lastArg is not a directory; mv cannot merge multiple files into one." exit 1
fi
argsLeft=$#
echo "Moves..."
for param in "$@"; do if [ $argsLeft -eq 1 ]; then echo "...Into the directory $param" # has to be a directory because -f $lastArg was dealt with earlier exit 0 fi if [ -d "$param" ]; then if [ ! -d "$lastArg" ]; then echo "Error: $lastArg is not a directory; mv cannot overwrite a non-directory with a directory." exit 1 fi if [ $argsLeft -eq $# ]; then echo "The directory ${param} (and anything inside it)..." else echo "And the directory ${param} (and anything inside it)..." fi else if [ $argsLeft -eq $# ]; then echo "The file ${param}..." else echo "And the file ${param}..." fi fi ((argsLeft--))
done

Some examples:

$ ls
dir1 dir2 file1 file2 file3 mvsim
$ ./mvsim file1 file2
Renames file file1 to file2, replacing file file2
$ ./mvsim file1 newfile
Renames file file1 to newfile
$ ./mvsim file1 dir1
Moves file file1 into the directory dir1
$ ./mvsim file1 file2 file3 dir1
Moves...
The file file1...
And the file file2...
And the file file3...
...Into the directory dir1
$ ./mvsim file1 file2 dir1 dir2
Moves...
The file file1...
And the file file2...
And the directory dir1 (and anything inside it)...
...Into the directory dir2
$ ./mvsim file1 file2 file3 # error - file3 isn't a directory
Error: file3 is not a directory; mv cannot merge multiple files into one.
$ ./mvsim -f -i file1 dir1 # options aren't parsed or filtered out
Error: -f does not exist.

1

Create an executable file safemv with contents:

#!/bin/bash
# Allows invocation with dryrun=1 and also protects from fraud attempts.
[ -n "$dryrun" ] && dryrun=echo
$dryrun mv "$@"

To test the substituted arguments run this file with dryrun=1, e.g.:

dryrun=1 ./safemv *.png /tmp/pngs

For actual use run this file without specifying dryrun:

./safemv *.png /tmp/pngs

This approach may be used with any potentially dangerous commands.

0

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