Linux one liners

Diff two directories

diff -rq /dir1 /dir2

Set suid

File: File executes as the user that owns the file, not the user that ran the file

chmod u+s

Set sgid

File: File executes as the group that owns the file
Dir: Files newly created in the directory have their group owner set to match the group owner of the directory

chmod u+s

chmod g+s

Set Sticky bit

File: no effect
Dir: User with write on the directory can only remove files that they own, they can not remove files owned by other users

chmod o+t

Tar + gzip on the fly in linux

# tar cvf - somedir | gzip -c > somedir.tar.gz

List all ips on ifconfig except loopback

ifconfig  | grep 'inet addr:'| grep -v '127.0.0.1' | cut -d: -f2 | awk '{ print $1}' | uniq

List sockets to Listen on in httpd.conf

cat /path/to/httpd.conf | grep -i listen | grep -v "#" | cut -d: -f1 | awk '{print $2}'  | sort -n | uniq

Find ips set to listen on httpd.conf

cat /path/to/httpd.conf | grep -i listen | grep -v "#" | cut -d: -f1 | awk '{print $2}'  | sort -n | uniq

Find sockets set to listen in all files under a directory

grep -Ri listen /path/to/vhosts | grep -v "#" | awk '{print $2}'  | sort -n  |uniq

Find ips set to listen in all files under a directory

grep -Ri listen /path/to/vhosts | grep -v "#" | awk '{print $2}'  | sort -n | cut -d: -f1 |uniq

find all ips set to listen in all httpd.conf files

locate httpd.conf | xargs grep -i listen | grep -v "#"  | awk '{print $2}'  | sort -n  | cut -d: -f1 | uniq

Scripts

some useful linux/unix scripts

linux dedupe problems?

Here’s a nice dedupe script i found:

#!/bin/bash
# Filename: dedupe.sh
# source: http://ithacafreesoftware.org/forum/viewtopic.php?f=7&t=326
# this file takes two text files as input
# sorts them and outputs lines from
# file 2 that do not exist in file 1
# into a new file called [file 1].clean

if [ -f "$1" ] && [ -f "$2" ]
then
    # sort both files
    sort -u $1 > $1.tmp;
    sort -u $2 > $2.tmp;
    comm -13 $1.tmp $2.tmp > $2.clean;
else
    echo "Usage: dedupe.sh file1 file2";
    echo "where file1 is the 'master' file";
    echo "and file2 is the file possibly containing duplicates";
fi