Check file existence in your directory

[calvinleung]

In the unix server, there shoud have a file which called abc.txt under each user directory , if I want to check if all user direcory have this file , to know which user do not have this file , what can i do ?

Thanks.

[Matti_Kurkela]

You can write a small script, that uses the information in /etc/passwd to find the usernames and home directories.

#!/bin/sh

USERFILE=abc.txt

# from this point on, read /etc/passwd as standard input
exec </etc/passwd

while read PASSWDLINE; do
    # username is the 1st field, home directory is 6th
    USERNAME=$(echo "$PASSWDLINE" | cut -d : -f 1)
    USERHOME=$(echo "$PASSWDLINE" | cut -d : -f 6)

    # see if the specified file exists
    if [ ! -f "$USERHOME/$USERFILE" ]; then
        echo "$USERNAME does not have the file $USERHOME/$USERFILE"
    fi
done

 In general, most "check if condition X is true, for each user" problems in Unix systems can be solved by a general method of "walk through /etc/passwd one line at a time: from each line, pick the user-specific information you need, then perform the check".

[Dennis Handly]

># from this point on, read /etc/passwd as standard input
>exec </etc/passwd

It is probably much easier to use awk than cut(1) and not use tricky stuff like exec:

awk -F: '{print $1, $6}' /etc/passwd | while read USERNAME USERHOME; do
    # username is the 1st field, home directory is 6th
    # see if the specified file exists
    if [ ! -f "$USERHOME/$USERFILE" ]; then
        echo "$USERNAME does not have the file $USERHOME/$USERFILE"
    fi
done