e. Exercises II
Absolute vs. Relative Paths
Starting from /Users/amanda/data
,
which of the following commands could Amanda use to navigate to her home directory,
which is /Users/amanda
?
cd .
cd /
cd /home/amanda
cd ../..
cd ~
cd home
cd ~/data/..
cd
cd ..
Solution
- No:
.
stands for the current directory. - No:
/
stands for the root directory. - No: Amanda’s home directory is
/Users/amanda
. - No: this command goes up two levels, i.e. ends in
/Users
. - Yes:
~
stands for the user’s home directory, in this case /Users/amanda
. - No: this command would navigate into a directory
home
in the current directory
if it exists. - Yes: unnecessarily complicated, but correct.
- Yes: shortcut to go back to the user’s home directory.
- Yes: goes up one level.
Relative Path Resolution
Using the filesystem diagram below, if pwd
displays /Users/thing
,
what will ls -F ../backup
display?
../backup: No such file or directory
2012-12-01 2013-01-08 2013-01-27
2012-12-01/ 2013-01-08/ 2013-01-27/
original/ pnas_final/ pnas_sub/
Solution
- No: there is a directory
backup
in /Users
. - No: this is the content of
Users/thing/backup
,
but with ..
, we asked for one level further up. - No: see previous explanation.
- Yes:
../backup/
refers to /Users/backup/
.
ls
Reading Comprehension
Using the filesystem diagram below,
if pwd
displays /Users/backup
,
and -r
tells ls
to display things in reverse order,
what command(s) will result in the following output:
pnas_sub/ pnas_final/ original/
ls pwd
ls -r -F
ls -r -F /Users/backup
Solution
- No:
pwd
is not the name of a directory. - Yes:
ls
without directory argument lists files and directories
in the current directory. - Yes: uses the absolute path explicitly.