Mfcttrf

I have been trying to find the answer to this question for awhile. I am writing a quick script to run a command based on output from awk.

ID_minimum=1000
for f in /etc/passwd;
do awk -F: -vID=$ID_minimum '$3>=1000 && $1!="nfsnobody" print "xfs_quota -x -c 'limit bsoft=5g bhard=6g $1' /home "' $f; 
done

The problems are that the -c argument takes a command in single quotes and I can't figure out how to properly escape that and also that $1 doesn't expand into the username.

essentially I am just trying to get it to output:

xfs_quota -x -c 'limit bsoft=5g bhard=6g userone' /home
xfs_quota -x -c 'limit bsoft=5g bhard=6g usertwo' /home

etc...

To run the command xfs_quota -x -c 'limit bsoft=5g bhard=6g USER' /home for each USER whose UID is at least $ID_minimum, consider parsing out those users first and then actually run the command, rather than trying to create a string representing the command that you want to run.

If you create the command string, you would have to eval it. This is fiddly and easy to get wrong. It's better to just get a list of usernames and then to run the command.

getent passwd |
awk -F: -v min="$ID_minimum:-1000" '$3 >= min && $1 != "nfsnobody" print $1 ' |
while IFS= read -r user; do
 xfs_quota -x -c "limit bsoft=5g bhard=6g $user" /home
done

Note that there is no actual need for single quotes around the argument after -c. Here I use double quotes because I want the shell to expand the $user variable which contains values extracted by awk.

I use $ID_minimum:-1000 when giving the value to the min variable in the awk command. This will expand to the value of $ID_minimum, or to 1000 if that variable is empty or not set.

for f in /etc/passwd;

This is a bit silly as there's really no loop with just one value.

But the issue seems to be printing single quotes from awk. You could escape them in the shell, but you could also use backslash-escapes within awk to print them. OOO is the character with numerical value OOO (in octal), so 47 is '. So this would be one way to do it:

awk -F: -vID=$ID_minimum '$3>=1000 && $1!="nfsnobody" 
 printf "xfs_quota -x -c 47limit bsoft=5g bhard=6g %s47 /homen", $1' /etc/passwd

You could use the similar escape in hex, x27, but it can get misinterpreted in some implementations if the following character is a valid hexadecimal digit. (And of course I assumed ASCII or an ASCII-compatible character set, e.g. UTF-8.)

Use the -f - option to awk to take the script from stdin and a here-document:

awk -F: -v "ID=$ID_minimum" -f - <<'EOT' /etc/passwd
$3>=1000 && $1!="nfsnobody"
 print "xfs_quota -x -c 'limit bsoft=5g bhard=6g "$1"' /home "
EOT

This did it.

awk -F: -vID=$ID_minimum '$3>=1000 && $1!="nfsnobody" print "xfs_quota -x -c '"'"'limit bsoft=5g bhard=6g ''"$1"'''"'"' /home "' /etc/passwd