issotm@sheik-kitty /tmp/test% git status                          [master|●2…1] On branch master                                                                                                                                                No commits yet                                                                                                                                                  Changes to be committed:                                                          (use "git rm --cached <file>..." to unstage)                                          new file:   main.c                                                              new file:   main.h                                                                                                                                      Untracked files:                                                                  (use "git add <file>..." to include in what will be committed)                        test.c                                                                                                                                                  issotm@sheik-kitty /tmp/test%                                     [master|●2…1] 

issotm@sheik-kitty /tmp/test% echo 'Hello Wordl!' >msg.txt         [master|✔]  issotm@sheik-kitty /tmp/test% git add msg.txt                     [master|✚1]  issotm@sheik-kitty /tmp/test% git commit -m 'Add message'         [master|●1]  [master 37bc80e] Add message                                                    1 file changed, 1 insertion(+)                                                issotm@sheik-kitty /tmp/test% cat msg.txt                          [master|✔]  Hello Wordl!                                                                   issotm@sheik-kitty /tmp/test% git log --oneline                    [master|✔]  37bc80e (HEAD -> master) Add message                                           91db0da Initial commit                                                         issotm@sheik-kitty /tmp/test% echo 'Hello Wordl!' >msg.txt         [master|✔]  

issotm@sheik-kitty /tmp/test% git status                          [master|●2…1] On branch master                                                                                                                                                No commits yet                                                                                                                                                  Changes to be committed:                                                          (use "git rm --cached <file>..." to unstage)                                          new file:   main.c                                                              new file:   main.h                                                                                                                                      Untracked files:                                                                  (use "git add <file>..." to include in what will be committed)                        test.c                                                                                                                                                  issotm@sheik-kitty /tmp/test%                                     [master|●2…1] 

[issotm@sheik-kitty tmp]$ echo 'Hello' >in.txt                        [issotm@sheik-kitty tmp]$ tr [:lower:] [:upper:] <in.txt