Update modify.md

rlpitts · web-flow · commit c244aab446ce · 2025-10-17T17:10:32.000+02:00
diff --git a/docs/modify.md b/docs/modify.md
@@ -17,109 +17,126 @@
 
 This section will show how to work with files and directories through the command line interface (CLI).
 
-### Directories 
+### Files 
 
-- **mkdir DIR**: Creates a directory DIR
-    - **mkdir -p DIR/SUBDIR**: creates a directory DIR with the subdirectory SUBDIR
-- **rm -r DIR**: Removes a directory DIR. The flag "-r" means recursively
-    - You can also add "-f". This means ignore nonexistent files and arguments, and never prompt. 
-    - You can add the option "-i". This means it will prompt before every removal. 
+To create files, you would normally use an editor (``nano``, ``vim``, ``emacs``, etc.), but you can also create an empty file with the command `touch`.
 
-!!! example "Examples: creating and removing directories"
+```bash 
+touch FILE
+```
 
-    Create a directory called ``mynewdir``
+You can remove files with ``rm``. You can use the flag/option ``-i`` to prompt before removing a file. Be aware that files removed with ``rm`` are deleted *permanently*---they generally cannot be restored (people have gotten lucky with system backup snapshots, but do not assume that those will be available).
 
-    ```bash
-    mkdir mynewdir
-    ```
+!!! example "Examples"
 
-    Create a directory called ``cooldir`` which has a subdirectory called ``fancydir``
+    Create a file called ``file.txt``
 
     ```bash
-    mkdir -p cooldir/fancydir
+    touch file.txt
     ```
 
-    Remove the directory ``mynewdir``
+    Remove the file ``file.txt``
 
     ```bash
-    rm -r mynewdir
+    rm file.txt
     ```
 
-### Files 
+!!! warning
 
-To create files, you would normally use an editor (``nano``, ``vim``, ``emacs``, etc.), but it is also possible to create an empty file with the command ``touch``.
+    If you do not add the flag/option "-i" the file will be deleted without prompting. Be careful!
 
-```bash 
-touch FILE
-```
+    Be **extra** careful using `rm -rf` with glob patterns (see [Wild Cards under The File System](../filesystem/#wild__cards) )! It is strongly recommended that you always test a pattern with `ls` and check that the output is what you expect before using `rm -rf` on that pattern.
 
-(The `touch` command is more often used to update the timestamps (specifically the latest access and modification times) of existing files.)
+### Directories 
 
-You can remove files with ``rm``. Again, you can use the flag/option ``-i`` to prompt before removing a file. Be aware that files removed with ``rm`` are deleted *permanently*---they generally cannot be restored (people have gotten lucky with system backup snapshots, but do not assume that those will be available).
+- **`mkdir DIR`**: Creates a directory DIR
+    - **`mkdir -p DIR/SUBDIR`**: creates a directory DIR with the subdirectory SUBDIR
+- **`rm -r DIR`**: Removes a directory DIR. The flag `-r` means recursively.
+    - You can also add `-f` (meaning force). This means ignore nonexistent files and arguments, and never ask before deleting the target.
+    - Again, you can add the option `-i`. This means it will prompt before every removal.
 
-!!! warning
+!!! example "Examples: creating and removing directories"
 
-    If you do not add the flag/option "-i" the file will be deleted without prompting. Be careful!
+    Create a directory called ``mynewdir``
 
-    Be **extra** careful using `rm -rf` with glob patterns (see [Wild Cards under The File System](../filesystem/#wild__cards) )! It is strongly recommended that you always test a pattern with `ls` and check that the output is what you expect before using `rm -rf` on that pattern.
-    
-!!! example "Examples"
+    ```bash
+    mkdir mynewdir
+    ```
 
-    Create a file called ``file.txt``
+    Create a directory called ``cooldir`` which has a subdirectory called ``fancydir``
 
     ```bash
-    touch file.txt
+    mkdir -p cooldir/fancydir
     ```
 
-    Remove the file ``file.txt``
+    Remove the directory ``mynewdir``
 
     ```bash
-    rm file.txt
+    rm -r mynewdir
     ```
-    
+
 ### Examples
 
 ???+ faq "Reminder"
 
-     - **mkdir DIR**: Create a directory DIR
-     - **rm -rf DIR**: Remove a directory DIR. The flag "-r" means recursively and "-f" means do so without asking for each file and subdirectory. Useful, but dangerous. Be careful!
-     - **cd**: Go to your home directory ($HOME)
-     - **cd DIR**: Change directory to DIR
-     - **cd ..**: Change directory to the parent directory of the current directory
-     - **cd -**: go back to the previous working directory
-     - **touch FILE**: create an empty file with the name FILE
-     - **rm FILE**: remove the file with the name FILE
-     - The command `pwd` tells you the current directory path.
+     - **`mkdir DIR`**: Create a directory DIR
+     - **`rm -rf DIR`**: Remove a directory DIR. The flag "-r" means recursively and "-f" means do so without asking for each file and subdirectory. Useful, but dangerous. Be careful!
+     - **`cd`**: Go to your home directory ($HOME)
+     - **`cd DIR`**: Change directory to DIR
+     - **`cd ..`**: Change directory to the parent directory of the current directory
+     - **`cd -`**: Go back to the previous working directory
+     - **`touch FILE`**: Create an empty file with the name FILE or update the timestamps of an existing file named FILE
+     - **`rm FILE`**: Remove the file with the name FILE
+     - **`pwd`**: print the current working directory path in full.
 
 !!! example "Creating directories, changing directories, removing directory and file, removing files by pattern"
 
     This example sequence will demonstrate some of the things we just learned, as well as the command `cd` and glob patterns from the previous section. 
 
     **HINT: Code-along!**
 
+    Create and remove directories:
+    
     ```bash
     [x_rebpi@tetralith1 ~]$ mkdir mytestdir
     [x_rebpi@tetralith1 ~]$ cd mytestdir/
     [x_rebpi@tetralith1 mytestdir]$ mkdir testdir1
     [x_rebpi@tetralith1 mytestdir]$ mkdir testdir2
     [x_rebpi@tetralith1 mytestdir]$ mkdir testdir3
+    [x_rebpi@tetralith1 mytestdir]$ ls
+    testdir1  testdir2  testdir3
     [x_rebpi@tetralith1 mytestdir]$ rm -rf testdir3
+    [x_rebpi@tetralith1 mytestdir]$ ls
+    testdir1  testdir2
+    ```
+
+    Create and remove files:
+    
+    ```bash    
     [x_rebpi@tetralith1 mytestdir]$ cd testdir1
     [x_rebpi@tetralith1 testdir1]$ touch file1.txt
     [x_rebpi@tetralith1 testdir1]$ touch file2.sh
     [x_rebpi@tetralith1 testdir1]$ touch file3.c
     [x_rebpi@tetralith1 testdir1]$ touch file4.dat
-    [x_rebpi@tetralith1 testdir1]$ touch file5.txt
-    [x_rebpi@tetralith1 testdir1]$ rm file5.txt
-    [x_rebpi@tetralith1 testdir1]$
-    [x_rebpi@tetralith1 testdir1]$ cd ..
-    [x_rebpi@tetralith1 mytestdir]$ cd testdir2/
-    [x_rebpi@tetralith1 testdir2]$ touch meow.txt
-    [x_rebpi@tetralith1 testdir2]$ touch catsmeow1.txt
-    [x_rebpi@tetralith1 testdir2]$ touch homeowners_assoc.txt
-    [x_rebpi@tetralith1 testdir2]$ ls *meow*.txt
-    [x_rebpi@tetralith1 testdir2]$ rm -r *meow{,1}.txt
+    [x_rebpi@tetralith1 testdir1]$ rm file4.dat
+    [x_rebpi@tetralith3 testdir1]$ rm -i file3.c
+    rm: remove regular empty file 'file3.c'? y
+    [x_rebpi@tetralith3 testdir1]$ ls
+    file1.txt  file2.sh
+    ```
+
+    Removing files by glob pattern (or why to always test a glob pattern with `ls` before using it with `rm`):
     
+    ```bash
+    [x_rebpi@tetralith1 testdir1]$ cd ../testdir2
+    [x_rebpi@tetralith1 testdir2]$ touch meow.txt
+    [x_rebpi@tetralith1 testdir2]$ touch catsmeow1.dat
+    [x_rebpi@tetralith1 testdir2]$ touch homeowners_assoc.odt
+    [x_rebpi@tetralith1 testdir2]$ ls *meow*
+    catsmeow1.dat  homeowners_assoc.odt  meow.txt
+    [x_rebpi@tetralith1 testdir2]$ rm -r *meow{,1}.??t
+    [x_rebpi@tetralith1 testdir2]$ ls
+    homeowners_assoc.odt
     ```
 
 !!! Note
@@ -138,10 +155,11 @@ You can remove files with ``rm``. Again, you can use the flag/option ``-i`` to p
 
 This command is used to copy files or directories.
 
-- **cp myfile.txt DIR/**: copy the file "myfile.txt" to the directory DIR
-- **cp DIR1/ DIR2/**: copy the directory DIR1 into the directory DIR2 (Note: overwrites existing files with same name)
-- **cp -R DIR1/ DIR2/**: copy the directory DIR1 and all subdirectories into the directory DIR2. 
-- **cp -i file.txt DIR/**: Interactive. It will ask before overwriting if there is a file with the same name. 
+- **`cp myfile.txt myfile2.txt`**: make a copy of "myfile.txt" named "myfile2.txt" 
+- **`cp myfile.txt DIR/`**: copy the file "myfile.txt" into the directory DIR
+- **`cp DIR1/ DIR2/`**: copy the directory DIR1 into the directory DIR2 (Note: only works if DIR1 contains no subdirectories)
+- **`cp -r DIR1/ DIR2/`**: copy the directory DIR1 and all subdirectories into the directory DIR2. 
+- **`cp -i file.txt DIR/`**: Interactive. It will ask before overwriting if there is a file with the same name. 
 
 !!! warning 
 
@@ -160,43 +178,48 @@ This command is used to copy files or directories.
        cd exercises
        cd mytestdir
        ```
+       
     2. Copy the file ``myfile.txt`` to the subdirectory ``testdir1``:
 
        ```bash
        cp myfile.txt testdir1
        ```
+       
     3. Create a new directory called ``testdir3`` inside ``testdir1``
 
        ```bash
        cd testdir1
        mkdir testdir3
        ```
+       
     4. Copy the new subdirectory ``testdir3`` to the directory ``testdir2``. Remember, "testdir2" is located outside "testdir1" and at the same "level". This can be done in more than one way. Remember you need the option ``-r`` (for recursive) when copying directories:
         a) "Go up one" and then copy:
            ```bash
            cd ..
            cp -r testdir1/testdir3 testdir2/
            ```
+           
         b) Copy will standing inside ``testdir1``
            ```bash
            cp -r testdir3 ../testdir2
            ```
+           
     5. If you give the full path while copying, this can be done from anywhere.
 
 ## mv - rename files/directories
 
-The command <code>mv</code> is used to rename files and directories, and to **move** a file or directory to another location.
+The command `mv` is used to rename files and directories, and to **move** a file or directory to another location.
 
-- **mv file1.txt file2.txt**: renames <code>file1.txt</code> to <code>file2.txt</code>
-- **mv DIR1/ DIR2/**: renames directory <code>DIR1</code> to directory <code>DIR2/</code>
-- **mv file1.txt DIR1/**: moves the file <code>file1.txt</code> into the directory <code>DIR1/</code>
-- **mv DIR1 DIR2/**: (note lack of forward slash after <code>DIR1</code>) moves directory <code>DIR1</code> into directory <code>DIR2/</code>.
-- **mv -i file1.txt file2.txt**: interactive. Asks before overwriting if there is already a file with the destination name.
-- **mv -i DIR1/ DIR2/**: interactive. Asks before overwriting, if there is already a directory with that name.
+- **`mv file1.txt file2.txt`**: renames `file1.txt` to `file2.txt`
+- **`mv DIR1/ DIR2/`**: renames directory `DIR1` to directory `DIR2/`
+- **`mv file1.txt DIR1/`**: moves the file `file1.txt` into the directory `DIR1/`
+- **`mv DIR1 DIR2/`**: (note lack of forward slash after `DIR1`) moves directory `DIR1` into directory `DIR2/`.
+- **`mv -i file1.txt file2.txt`**: interactive. Asks before overwriting if there is already a file with the destination name.
+- **`mv -i DIR1/ DIR2/`**: interactive. Asks before overwriting, if there is already a directory with that name.
 
 !!! tip
 
-    <code>mv</code> complains if there is already a file/directory with the new name. You can force the renaming with "-f" at the cost of the disappearence of the file that previously held the name.
+    `mv` complains if there is already a file/directory with the new name. You can force the renaming with "-f" at the cost of the disappearence of the file that previously held the name.
 
 ### Exercise 
 
@@ -219,37 +242,43 @@ The command <code>mv</code> is used to rename files and directories, and to **mo
        touch bfile.txt
        touch cfile.txt
        ```
+       
     2. I make the directory ``newdir`` and the subdirectory ``subdir``
 
        ```bash 
        mkdir newdir
        cd newdir
        mkdir subdir
        ```
+       
     3. I create a file named ``newfile.dat``
 
        ```bash
        cd subdir
        touch newfile.dat
        ```
+       
     4. I name the file ``secondfile.txt`` and move it into ``subdir``
 
        ```bash
        cd ..
        touch secondfile.txt
        mv secondfile.txt subdir
        ```
+       
     5. I rename the first directory (top-level directory) I created, calling it ``fancydir``
 
        ```bash
        cd ..
        mv newdir fancydir
        ```
+       
     6. I remove the file ``afile.txt`` while working in the directory outside of ``fancydir`` (previously called ``newdir``)
 
        ```bash
        rm fancydir/afile.txt
        ```
+       
     7. I remove the subdirectory ``subdir`` while outside the directory ``fancydir``
 
        ```bash
@@ -299,4 +328,3 @@ ln -s real-file-or-lib link-name
     - The command to rename files and directories is ``mv``
     - Symbolic links are pointers to another file or directory
     - Always test glob patterns with ``ls`` before using the same patterns with ``rm -r`` to remove files in bulk.
-
