How to get HOME, given USER?

Question

I have an USER variable in my script, and I want to see his HOME path based on the USER variable. How can I do that?

Answer 1

There is a utility which will lookup user information regardless of whether that information is stored in local files such as /etc/passwd or in LDAP or some other method. It's called getent.

In order to get user information out of it, you run getent passwd $USER. You'll get a line back that looks like:

[jenny@sameen ~]$ getent passwd jenny
jenny:*:1001:1001:Jenny Dybedahl:/home/jenny:/usr/local/bin/bash

Now you can simply cut out the home dir from it, e.g. by using cut, like so:

[jenny@sameen ~]$ getent passwd jenny | cut -d: -f6
/home/jenny

Answer 2

You can use eval to get someone's home directory.

eval echo "~$USER"

At least for local users this works for sure. I don't know if remote users like LDAP are handled with eval.

Answer 3

The usual place is /home/$USER, but that does not have to be universal. The definitive place to search for such information is inside the file /etc/passwd.

That file is world readable (anyone could read it), so any user has access to its contents.
If the $USER exists in the file, the entry previous to last is the user HOME directory.

This will select the entry and print the HOME directory:

awk -v FS=':' -v user="$USER" '($1==user) {print $6}' "/etc/passwd"

For more complex (remote) systems, getent is the usual command to get users information from the NSS (Name Service Switch libraries) system.

A command of

getent passwd "$USER" | cut -d : -f 6

Will provide equivalent information (if available).

Answer 4

If the user doesn't exist, getent will return an error.

Here's a small shell function that doesn't ignore the exit code of getent:

get_home() {
  local result; result="$(getent passwd "$1")" || return
  echo $result | cut -d : -f 6
}

Here's a usage example:

da_home="$(get_home missing_user)" || {
  echo 'User does NOT exist!'; exit 1
}

# Now do something with $da_home
echo "Home directory is: '$da_home'"

Answer 5

If you are logged in as root, if you know USER's password, or if the USER has no password, the following is yet another option:

    su -c 'echo ~' ${USER}

Under standard su behavior, if USER is undefined or empty, then su will attempt to run the command as root.

If the value of USER is not a valid user name, then an appropriate error will be raised: su: user <user> does not exist.

There are already plenty of good answers here but this may still help someone.

Answer 6

getent is not reliable...

getent will not work as expected for usernames consisting of all numerics.

Consider username of '0029', getent will return system rpc (in my case, rpc may have a different uid on your system) user details and not username 0029 details.

chown and a few other system commands will also have issues... see https://access.redhat.com/solutions/310363

Also see getent man page.

/etc/passwd is readable by all, so try

'awk -F':' -v U=$USER '$1==U {print $6}' /etc/passwd

Answer 7

Several reasonable solutions are already posted, but all have issues. For example:

• getent passwd "${MY_USER}" | cut -d: -f6: Will fail for numeric usernames, as pointed out by @kikenchitai. getent passwd "<value>" assumes UIDs when given numeric values.

• eval echo "~${MY_USER}": eval is vulnerable to several security concerns. Additionally, this will fail for usernames with spaces or other interpreted characters.

• awk -v FS=':' -v user="${MY_USER}" '($1==user) {print $6}' "/etc/passwd": /etc/passwd does not provide a complete representation of users, hence the need for getent. See read files directly VS getent.

  Note: See discussion on using getent passwd here instead of /etc/passwd in comments. In short, one critical caveat of getent passwd is that remote users are often not bulk-listable. getent passwd only lists local users in many cases, whereas getent passwd <UID> also queries remote user databases.

• su -c 'echo ~' "${MY_USER}": Requires elevated access, among other security concerns (as mentioned by @derobert).

• getent passwd | grep "^${MY_USER}:": Subject to regex injection. Also subject to getent passwd only querying the local user database in many cases.

This is the most reliable solution I've seen so far:

getent passwd "$(id -u "${MY_USER}")" | cut -d: -f6

Explanation:

• id -u "${MY_USER}": Get the user's UID. This should reliably work with local and non-local users (e.g., LDAP users via SSSD).
• getent passwd "<UID>": Get passwd data for the given UID. This will search all user databases via Name Service Switch (not just /etc/passwd).
• cut -d: -f6: Pull the home directory field. This should be consistent across the majority of systems. Most (all?) distributions both assign the sixth field to the home directory and explicitly reserve colons as delimiters without escaping.