I use FreeBSD
> uname -sr
FreeBSD 6.3-RELEASE
When I query
> grep `whoami` /etc/passwd
It shows me the information I want:
But when I try getting it in a tcsh script:
#!/bin/tcsh
set login = `whoami`
echo $login
set query = `grep $login /etc/passwd`
echo $query
it brings me the following:
dolg_gr
echo: No match.
Why 'No match' ? How can I get the string it provides me at the command shell in the $query variable?
This isn't a problem with grep - it's a problem with the unquoted variable expansion in
echo $query
and the fact that the matched line returned by grep contains the globbing character *. In tcsh, the default behavior for unsuccessful globs is similar to bash's failglob option - the error is telling you that there is no filename match for your passwd string:
$ tcsh -c 'echo dol_gr:*:3291'
echo: No match.
As mentioned by Stéphane Chazelas, the right way to quote variable expansions in (t)csh is to use the q modifier. Also note that tcsh's `...` splits on SPC, TAB and NL when unquoted and on NL only when quoted:
set query = "`grep $login:q /etc/passwd`"
echo $query:q
echo $query:q. echo "$query" won't work for values of $query that contain newline characters. echo "$query:q" won't work if it contains backslash followed by newline (and avoid echo for the usual reasons). But maybe the better advise here would be to stay away from (t)csh.
Feb 28, 2021 at 16:42
$login:q is not guaranteed to quote properly when inside those quoted backticks. See for instance: a=$'a\\\nb c' tcsh -c 'printf "<%s>\n" "`printf %s\\n $a:q`"' which removes the backslash and splits into a, b and c. I don't even know if it's possible to get it right here and have given up on tcsh for this kind of reason over 25 years ago).
Feb 28, 2021 at 18:07
getent passwd `whoami`?getent passwdwould get it from the/etc/passwdfile. It's safer as yourgrepwould pick out irrelevant entries if your username was something likerooornolo.