Find the depth of the current path

问题

How can I write a shell script to find the depth of the current path?

Assuming I am in:

/home/user/test/test1/test2/test3

It should return 6.

回答1:

A simple approach in fish:

count (string split / $PWD)

回答2:

With shell parameter expansions, no external commands:

$ var=${PWD//[!\/]}
$ echo ${#var}
6

The first expansion removes all characters that are not /; the second one prints the length of var.

---

Explanations with details for support by POSIX shell or Bash (the links in parentheses go to the corresponding sections in the POSIX standard or the Bash manual):

• $PWD contains the path to the current working directory. (sh/Bash)
• The ${parameter/pattern/string} expansion replaces the first occurrence of pattern in the expansion of parameter with string. (Bash)
  • If the first slash is doubled (as in our case), all occurrences are replaced.
  • If string is empty, the slash after pattern is optional (as in our case).
• The pattern [!\/] is a bracket expression and stands for "any character other than slash". (sh/Bash)
  • The slash has to be escaped, \/, or it is interpreted as ending the pattern.
  • ! as the first character in a bracket expression negates the expression: any character other than the ones in the expression match the pattern. POSIX sh requires support for ! and says the behaviour for using ^ is undefined; Bash supports both ! and ^. Notice that this is not a bracket expression as seen in regular expressions, where only ^ is valid.
• ${#parameter} expands to the length of parameter. (sh/Bash)

回答3:

You could count the number of slashes in the current path:

pwd | awk -F"/" '{print NF-1}'

回答4:

Assuming you don't have trailing "/", you can just count the "/".

So you would

• Remove everything that is not a "/"

• Count the length of the resulting string

In fish, this would be done with something like

string replace --regex --all '[^/]' '' -- $PWD | string length

The regular expression - [^/] here matches every single character that is not a "/". With "--all", this will be done as often as possible, and replace it with '', i.e. nothing.

The -- is the option separator, so that nothing in the argument is interpreted as an option (otherwise you'd have issues if an argument started with a "-a").

$PWD is the current directory.

string length simply outputs the length of its input.

回答5:

You can do this using a pipeline. pipe string into grep with the -o option. This prints out each "/" on a new line. pipe again into wc -l counts the number of lines printed.

echo "$path_str" | grep -o '/' - | wc -l

回答6:

Using perl :

echo '/home/user/test/test1/test2/test3' | 
perl -lne '@_ = split /\//; print scalar @_ -1'

Output

6

回答7:

You could use find just like that :

find / -printf "%d %p\n" 2>/dev/null | grep "$PWD$" | awk '{print $1}'

Maybe not the most efficient, but handles slashes well.

来源：https://stackoverflow.com/questions/48816827/find-the-depth-of-the-current-path