Remove part of path on Unix

I'm trying to remove part of the path in a string. I have the path:

/path/to/file/drive/file/path/

I want to remove the first part /path/to/file/drive and produce the output:

file/path/

Note: I have several paths in a while loop, with the same /path/to/file/drive in all of them, but I'm just looking for the 'how to' on removing the desired string.

I found some examples, but I can't get them to work:

echo /path/to/file/drive/file/path/ | sed 's:/path/to/file/drive:\2:'
echo /path/to/file/drive/file/path/ | sed 's:/path/to/file/drive:2'

\2 being the second part of the string and I'm clearly doing something wrong...maybe there is an easier way?

If you wanted to remove a certain NUMBER of path components, you should use cut with -d'/'. For example, if path=/home/dude/some/deepish/dir:

To remove the first two components:

# (Add 2 to the number of components to remove to get the value to pass to -f)
echo $path | cut -d'/' -f4-
# output:
# some/deepish/dir

To keep the first two components:

echo $path | cut -d'/' -f-3
# output:
# /home/dude

To remove the last two components (rev reverses the string):

echo $path | rev | cut -d'/' -f4- | rev
# output:
# /home/dude/some

To keep the last three components:

echo $path | rev | cut -d'/' -f-3 | rev
# output:
# some/deepish/dir

Or, if you want to remove everything before a particular component, sed would work:

echo $path | sed 's/.*\(some\)/\1/g'
# output:
# some/deepish/dir

Or after a particular component:

echo $path | sed 's/\(dude\).*/\1/g'
# output:
# /home/dude

It's even easier if you don't want to keep the component you're specifying:

echo $path | sed 's/some.*//g'
# output:
# /home/dude/

And if you want to be consistent you can match the trailing slash too:

echo $path | sed 's/\/some.*//g'
# output:
# /home/dude

Of course, if you're matching several slashes, you should switch the sed delimiter:

echo $path | sed 's!/some.*!!g'
# output:
# /home/dude

Note that these examples all use absolute paths, you'll have to play around to make them work with relative paths.

You can also use POSIX shell variable expansion to do this.

path=/path/to/file/drive/file/path/
echo ${path#/path/to/file/drive/}

The #.. part strips off a leading matching string when the variable is expanded; this is especially useful if your strings are already in shell variables, like if you're using a for loop. You can strip matching strings (e.g., an extension) from the end of a variable also, using %.... See the bash man page for the gory details.

If you don't want to hardcode the part you're removing:

$ s='/path/to/file/drive/file/path/'
$ echo ${s#$(dirname "$(dirname "$s")")/}
file/path/

One way to do this with sed is

echo /path/to/file/drive/file/path/ | sed 's:^/path/to/file/drive/::'

If you want to remove the first N parts of the path, you could of course use N calls to dirname, as in glenn's answer, but it's probably easier to use globbing:

path=/path/to/file/drive/file/path/
echo "${path#*/*/*/*/*/}"   #  file/path/

Specifically, ${path#*/*/*/*/*/} means "return $path minus the shortest prefix that contains 5 slashes".

Using ${path#/path/to/file/drive/} as suggested by evil otto is certainly the typical/best way to do this, but since there are many sed suggestions it is worth pointing out that sed is overkill if you are working with a fixed string. You can also do:

echo $PATH | cut -b 21-

To discard the first 20 characters. Similarly, you can use ${PATH:20} in bash or $PATH[20,-1] in zsh.

Pure bash, without hard coding the answer

basenames()
{
  local d="${2}"
  for ((x=0; x<"${1}"; x++)); do
    d="${d%/*}"
  done
  echo "${2#"${d}"/}"
}

• Argument 1 - How many levels do you want to keep (2 in the original question)
• Argument 2 - The full path

Taken from vsi_common(original version)

Here's a solution using simple bash syntax that accommodates variables (in case you don't want to hard code full paths), removes the need for piping stdin to sed, and includes a for loop, for good measure:

FULLPATH="/path/to/file/drive/file/path/"
SUBPATH="/path/to/file/drive/"
for i in $FULLPATH;
do
echo ${i#$SUBPATH}
done

as mentioned above by @evil otto, the # symbol is used to remove a prefix in this scenario.