gistfile1.txt

mbp-pawe:_ikke_ pawel$ git init
Initialized empty Git repository in /Users/pawel/gitEx/_ikke_/.git/
mbp-pawe:_ikke_ pawel$ echo "text from master" > testFile
mbp-pawe:_ikke_ pawel$ git add testFile
mbp-pawe:_ikke_ pawel$ git commit -m "Added testFile"
[master (root-commit) b3ecf8d] Added testFile
 1 file changed, 1 insertion(+)
 create mode 100644 testFile
mbp-pawe:_ikke_ pawel$ git branch secondBranch
mbp-pawe:_ikke_ pawel$ git checkout secondBranch 
Switched to branch 'secondBranch'
mbp-pawe:_ikke_ pawel$ echo "text from secondBranch" > testFile 
mbp-pawe:_ikke_ pawel$ git checkout master 
M	testFile
Switched to branch 'master'
mbp-pawe:_ikke_ pawel$ # It haven't show error