Find all users home directories listed using grep from /etc/passwd

greptext processing

I have a question similar to another one on this site where the individual had to find a list of all users using grep or awk from /etc/passwd. That worked for me but I've tried translating it to find and list the home directories of them also. I already know you can't do it in one line so I know I would use a pipeline. I've done my research online but I can't figure it out the problem is. If I use grep and do something like the following:

   grep -oE '^[/*/]$' /etc/passwd

…i t would probably give me an error or it will also show me the /bin/bash files which is not what I want. I just need the user names and their home directories listed using grep! I'm also not sure if the * will show other forward-slashes as characters, as some home directories have more than just two /'s (forward-slashes).

Best Answer

Grep is really not the tool for parsing out data this way; grep is more for pattern matching and you're trying to do text-processing. You would want to use awk.

awk -F":" '$7 == "/bin/false" {print "User: "$1 "Home Dir: "$6}' /etc/passwd

awk – The command
-F":" – Sets the data delimiter to :
$7 == "/bin/false" – Checks if the 7th data column is /bin/false
{print "User: "$1 "Home Dir: "$6}' – Says to print the first column and sixth column in the specified format.
/etc/passwd – Is the file we're processing

Related Solutions

Command-Line Grep – Params to Return Only File Names

   -l, --files-with-matches
          Suppress normal output; instead print the  name  of  each  input
          file  from  which  output would normally have been printed.  The
          scanning will stop on the first  match.   (-l  is  specified  by
          POSIX.)

from grep manpage

How to grep thousands of files in a directory for hundreds of strings in a file

You can pass a directory as a target to grep with -R and a file of input patterns with -f:

  -f FILE, --file=FILE
          Obtain patterns from FILE, one per line.  If this option is used
          multiple  times  or  is  combined with the -e (--regexp) option,
          search for all patterns given.  The  empty  file  contains  zero
          patterns, and therefore matches nothing.

   -R, --dereference-recursive
          Read all files under each directory,  recursively.   Follow  all
          symbolic links, unlike -r.

So, you're looking for:

grep -Ff subset.txt -r objects/

You can get the list of matching files with:

grep -Flf subset.txt -r objects/

So, if your final list isn't too long, you can just do:

 mv $(grep -Flf subset.txt -r objects/) new_dir/

If that returns an argument list too long error, use:

grep -Flf subset.txt -r objects/ | xargs -I{} mv {} bar/

And if your file names can contain spaces or other strange characters, use (assuming GNU grep):

grep -FZlf subset.txt -r objects/ | xargs -0I{} mv {} bar/

Finally, if you want to exclude binary files, use:

grep -IFZlf subset.txt -r objects/ | xargs -0I{} mv {} bar/

Best Answer

Related Solutions

Command-Line Grep – Params to Return Only File Names

How to grep thousands of files in a directory for hundreds of strings in a file

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