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RHCSA File System

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Question

Copy the file /etc/fstab to /var/tmp.

Configure the permissions of /var/tmp/fstab so that:
the file /var/tmp/fstab is owned by the root user
the file /var/tmp/fstab belong to the group root
the file /var/tmp/fstab should not be execubable by anyone
the user "natasha" is able to read and write /var/tmp/fstab
the user "harry" can neither write nor read /var/tmp/fstab
all other users (current or future) have the ability to read /var/tmp/fstab

Solution

cp /etc/fstab /var/tmp
chown root:root /var/tmp/fstab
chmod a-x /var/tmp/fstab

# Grant read and write permissions to the user natasha
setfacl -m u:natasha:rw /var/tmp/fstab
# Deny all permissions to the user harry
setfacl -m u:harry:--- /var/tmp/fstab
# Allow all other users (current and future) to read the file
chmod o+r /var/tmp/fstab

# Verify the permissions
ls -l /var/tmp/fstab
# -rw-rw-r--+ 1 root root 666 Jan 15 21:50 /var/tmp/fstab
getfacl /var/tmp/fstab
# getfacl: Removing leading '/' from absolute path names
# # file: var/tmp/fstab
# # owner: root
# # group: root
# user::rw-
# user:harry:---
# user:natasha:rw-
# group::r--
# mask::rw-
# other::r--

Question: Find all files

Find all files and directories which is created by a user "natasha" in to this system and copy it into a "/root/natashafiles" directory.

Solution

# create dir
mkdir -p /root/natashafiles
# find and copy
find / -user natasha -exec cp -r --parents {} /root/natashafiles \; 2>/dev/null

# verify
ls -lR /root/natashafiles

Question: grep

Find all strings "ich" from "/usr/share/dict/words" file and copy that strings in a /root/lines file.

Solution

grep "ich" /usr/share/dict/words > /root/lines

# Using Backslash (\)
grep "a\*b" /path/to/file 

# Using Single Quotes (')
grep 'a*b' /path/to/file

# search pattern as a fixed string
grep -F "a*b" /path/to/file