Rename file in Linux if file exist in a single command - linux

There is need that I want to rename file in Linux if file exist in a single command.
Suppose I want to search test.text file and I want to replace it with test.text.bak then I fire the following command
find / -name test.text
if it exist then I fire the command
mv test.text test.text.bak
In this scenario I am executing two commands but I want this should be happen in single command.
Thanks

Just:
mv test.text test.test.bak
If the file doesn't exist nothing will be renamed.
To supress the error message, when no file exits, use that syntax:
mv test.text test.test.bak 2>/dev/null

If you want to find test.txt somewhere in a subdirectory of dir and move it, try
find dir -name test.txt -exec mv {} {}.bak \;
This will move all files matching the conditions. If you want to traverse from the current directory, use . as the directory instead of dir.
Technically, this will spawn a separate command in a separate process for each file matched by find, but it's "one command" in the sense that you are using find as the only command you are actually starting yourself. (Think of find as a crude programming language if you will.)

for FILE in `find . -name test.test 2>/dev/null`; do mv $FILE $FILE.bak; done
This will search all the files named "test.test" in current as well as in child direcroties and then rename each file to .bak

Related

Bash script to sort files into sub folders based on extension

I have the following structure:
FolderA
Sub1
Sub2
filexx.csv
filexx.doc
FolderB
Sub1
Sub2
fileyy.csv
fileyy.doc
I want to write a script that will move the .csv files into the folder sub1 for each parent directory (Folder A, Folder B and so on) giving me the following structure:
FolderA
Sub1
filexx.csv
Sub2
filexx.doc
FolderB
Sub1
fileyy.csv
Sub2
fileyy.doc
This is what I have till now but I get the error mv: cannot stat *.csv: No such file or directory
for f in */*/*.csv; do
mv -v "$f" */*/Sub1;
done
for f in */*/*.doc; do
mv -v "$f" */*/Sub2;
done
I am new to bash scripting so please forgive me if I have made a very obvious mistake. I know I can do this in Python as well but it will be lengthier which is why I would like a solution using linux commands.
find . -name "*.csv" -type f -execdir mv '{}' Sub1/ \;
Using find, search for all files with the extension .csv and then when we find them, execute a move command from within the directory containing the files, moving the files to directory Sub1
find . -name "*.doc" -type f -execdir mv '{}' Sub2/ \;
Follow the same principle for files with the extension .doc but this time, move the files to Sub2.
I believe you are getting this error because no file matched your wildcard. When it happens, the for loop will give $f the value of the wildcard itself. You are basically trying to move the file *.csv which does not exist.
To prevent this behavior, you can add shopt -s nullglob at the top of your script. When using this, if no file is found, your script won't enter the loop.
My advise is, make sure you run your script from the correct location when using wildcards like this. But maybe what you meant to do by writing */*/*.csv is to recursively match all the csv files. If that's what you intended to do, this is not the right way to do it.
To recursively match all csv/doc/etc files using native bash you can add shopt -s globstar to the top of your script and use **/*.csv as wildcard
#!/bin/bash
shopt -s globstar nullglob
for f in **/*.csv; do
mv "$f" Destination/ # Note that $f is surrounded by "" to handle whitespaces in filenames
done
You could also use the find (1) utility to achieve that. But if you're planning to do more processing on the files than just moving them, a for loop might be cleaner as you won't have to inline everything in the same command.
Side note : "Linux commands" as you say are actually not Linux commands, they are part of the GNU utilities (https://www.gnu.org/gnu/linux-and-gnu.en.html)
If csv files you want to move are in the top directories (from the point of view of the current directory), but not in the subdirectories of them, then simply:
#!/bin/bash
for dir in */; do
mv -v "$dir"*.csv "${dir}Sub1/"
mv -v "$dir"*.doc "${dir}Sub2/"
done
If the files in all subdirectories are wanted to be moved similarly, then:
shopt -s globstar
for file in **/*.csv; do
mv -v "$file" "${file%/*}/Sub1/"
done
for file in **/*.doc; do
mv -v "$file" "${file%/*}/Sub2/"
done
Note that, the directories Sub1 and Sub2 are relative to the directory where csv and doc files reside.

Loop through a directory with any level of depth

I want to execute a command on all files present on all levels in the directory. It may have any number of files and sub directories. Even these sub directories may contain any number of files and subdirectories. I want to do this using shell script. As I am new to this field can any one suggest me a way out.
You can use the command "find" with "xargs" after "|"(pipe).
Example: Suppose that I want to remove all files that have ".txt" extension on "Documents" directory:
find Documents -iname *.txt |xargs rm -f
Helps?
You can use a recursive command that uses wildcard characters (*) like so:
for dir in ~/dev/myproject/*; do (cd "$dir" && git status); done
If you want to apply commands on the individual files you should use the find command and execute commands on it like so:
find yourdirectory -type f -exec echo "File found: '{}'" \;
What this does:
finds all the items in the directory yourdirectory
that have the type f - so are a file
runs an exec on each file
Use find:
find -type f -exec COMMAND {} \;
-f applies the command only to files, not to directories. The command is recursive by default.

Shell Script to Recursively Loop Through Directory and print location of important files

So I am trying to write a command line shell script or a shell script that will be able to recursively loop through a directory, all its files, and sub-directories for certain files and then print the location of these files to a text file.
I know that this is possible using BASH commands such as find, locate, exec, and >.
This is what I have so far. find <top-directory> -name '*.class' -exec locate {} > location.txt \;
This does not work though. Can any BASH, Shell scripting experts help me out please?
Thank-you for reading this.
The default behavior of find (if you don't specify any other action) is to print the filename. So you can simply do:
find <top-directory> -name '*.class' > location.txt
Or if you want to be explicit about it:
find <top-directory> -name '*.class' -print > location.txt
You can save the redirection by using find's -fprint option:
find <top-directory> -name '*.class' -fprint location.txt
From the man page:
-fprint file
[...] print the full file name into file file. If file does not exist when find is run, it is created; if it does exist, it is truncated.
A less preferred way to do it is to use ls:
ls -d $PWD**/* | grep class
let's break it down:
ls -d # lists the directory (returns `.`)
ls -d $PWD # lists the directory - but this time $PWD will provide full path
ls -d $PWD/** # list the directory with full-path and every file under this directory (not recursively) - an effect which is due to `/**` part
ls -d $PWD/**/* # same like previous one, only that now do it recursively to the folders below (achieved by adding the `/*` at the end)
A better way of doing it:
After reading this due to recommendation from Charles Duffy, it appears as a bad idea to use both ls as well as find (article also says: "find is just as bad as ls in this context".) The reason it's a bad idea is because you can't control the output of ls: for example, you can't configure ls to terminate filenames with NUL. The reason it's problematic is that unix allows all kind of weird characters in a file-name (newline, pipe etc) and will "break" ls in a way you can't anticipate.
Better use a shell script for the task, and it's pretty simple task too:
Create a file my_script.sh, edit the file to contain:
for i in **/*; do
echo $PWD/$i
done
Give it execute permissions (by running: chmod +x my_script.sh).
Run it from the same directory with:
./my_script.sh
and you're good to go!

Unix: traverse a directory

I need to traverse a directory so starting in one directory and going deeper into difference sub directories. However I also need to be able to have access to each individual file to modify the file. Is there already a command to do this or will I have to write a script? Could someone provide some code to help me with this task? Thanks.
The find command is just the tool for that. Its -exec flag or -print0 in combination with xargs -0 allows fine-grained control over what to do with each file.
Example: Replace all foo's by bar's in all files in /tmp and subdirectories.
find /tmp -type f -exec sed -i -e 's/foo/bar/' '{}' ';'
for i in `find` ; do
if [ -d $i ] ; then do something with a directory ; fi
if [ -f $i ] ; then do something with a file etc. ; fi
done
This will return the whole tree (recursively) in the current directory in a list that the loop will go through.
This can be easily achieved by mixing find, xargs, sed (or other file modification command).
For example:
$ find /path/to/base/dir -type f -name '*.properties' | xargs sed -ie '/^#/d'
This will filter all files with file extension .properties.
The xargs command will feed the file path generated by find command into the sed command.
The sed command will delete all lines start with # in the files (feed by xargs).
Command combination in this way is very flexible.
For example, find command have different parameters so you can filter by user name, file size, file path (eg: under /test/ subfolder), file modification time.
Another dimension of flexibility is how and what to change in your file. For ex, sed command allows you to make changes on file in applying substitution (specify via regular expressions). Similarly, you can use gzip to compress the file. And so on ...
You would usually use the find command. On Linux, you have the GNU version, of course. It has many extra (and useful) options. Both will allow you to execute a command (eg a shell script) on the files as they are found.
The exact details of how to make changes to the file depend on the change you want to make to the file. That is probably best scripted, with find running the script:
POSIX or GNU:
find . -type f -exec your_script '{}' +
This will run your script once for a group of files with those names provided as arguments. If you want to do it one file at a time, replace the + with ';' (or \;).
I am assuming SearchMe is the example directory name you need to traverse completely.
I am also assuming, since it was not specified, the files you want to modify are all text file. Is this correct?
In such scenario I would suggest using the command:
find SearchMe -type f -exec vi {} \;
If you are not familiar with vi editor, just use another one (nano, emacs, kate, kwrite, gedit, etc.) and it should work as well.
Bash 4+
shopt -s globstar
for file in **
do
if [ -f "$file" ];then
# do some processing to your file here
# where the find command can't do conveniently
fi
done

Copying files in multiple subdirectories in the Linux command line

Let's say I have the following subdirectories
./a/, ./b/, ./c/, ...
That is, in my current working directory are these subdirectories a/, b/ and c/, and in each of these subdirectories are files. In directory a/ is the file a.in, in directory b/ is the file b.in and so forth.
I now want to copy each .in file to a .out file, that is, a.in to a.out and b.in to b.out, and I want them to reside in the directories they were copied from. So a.out will be found in directory a/.
I've tried various different approaches, such as
find ./ -name '*.in'|cp * *.out
which doesn't work because it thinks *.out is a directory. Also tried
ls -d */ | cd; cp *.in *.out
but it that would list the subdirectories, go into each one of them, but won't let cp do it's work (which still doesn't work)
The
find ./ -name '*.in'
command works fine. Is there a way to pipe arguments to an assignment operator? E.g.
find ./ -name '*.in'| assign filename=|cp filename filename.out
where assign filename= gives filename the value of each .in file. In fact, it would be even better if the assignment could get rid of the .in file extension, then instead of getting a.in.out we would get the preferred a.out
Thank you for your time.
Let the shell help you out:
find . -name '*.in' | while read old; do
new=${old%.in}.out # strips the .in and adds .out
cp "$old" "$new"
done
I just took the find command you said works and let bash read its output one filename at a time. So the bash while loop gets the filenames one at a time, does a little substitution, and a straight copy. Nice and easy (but not tested!).
Try a for loop:
for f in */*.in; do
cp $f ${f%.in}.out;
done
The glob should catch all the files one directory down that have a .in extension. In the cp command, it strips off the .in suffix and then appends a .out (see Variable Mangling in Bash with String Operators)
Alternatively, if you want to recurse into every subdirectory (not just 1 level deep) replace the glob with a find:
for f in $(find . -name '*.in'); do
cp $f ${f%.in}.out;
done
This should do the trick!
for f in `find . -type f -name "*.in"`; do cp $f `echo $f | sed 's/in$/out/g'`; done

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