Table of Contents
Resize image using imagemagick
source: .http://www.cyberciti.biz/faq/bash-loop-over-file/
for f in *.c; do echo "Processing $f file.."; done
#!/bin/bash FILES=/path/to/* for f in $FILES do echo "Processing $f file..." # take action on each file. $f store current file name cat $f done
convert rose.jpg -resize 50% rose.png
cannon raw image cr2
http://marc.merlins.org/linux/technotes/cr2_dcraw_jhead.html
yum install dcraw for i in *.cr2; do dcraw -c -q 0 -w -H 5 -b 8 $i | cjpeg -quality 80 > $i.jpg; done mkdir jpgs for i in *.CR2; do dcraw -c -q 3 -w -H 5 -b 10 $i | cjpeg -quality 90 > ./jpgs/$i.jpg; done
Watch dd
source: .http://de.wikipedia.org/wiki/Dd_%28Unix%29
sudo killall -USR1 dd
Alternatively, you can use the watch command to execute kill at a set interval.
watch -n 2 kill -USR1 8789 watch -n 2 killall -USR1 dd
Convert ogv to mp4
ffmpeg -i INPUT -vcodec libx264 "OUTPUT.mp4" ffmpeg -i openstack_workflow_cem.ogv -vcodec mpeg4 -qscale 0 -acodec libmp3lame openstack_workflow_cem.avi
Append Date time to filename
now=$(date +"%m_%d_%Y") echo "Filename : /nas/backup_$now.sql"
Perl modules installation
1. Tee
tee: read from stdin and write to stdout AND file.
ls -lsa | tee outfile
The following command will take a backup of the crontab entries, and pass the crontab entries as an input to sed command which will do the substituion. After the substitution, it will be added as a new cron job.
crontab -l | tee crontab-backup.txt | sed 's/old/new/' | crontab –
2. Multiple default routes ip
2.1 Linux command
To view all the current rules, use the ip command as shown below:
# ip rule show 0: from all lookup local 32766: from all lookup main 32767: from all lookup default
First, take a backup of the rt_Tables before making any changes.
cd /etc/iproute2 cp rt_tables rt_tables.orig
Next, create a new policy routing table entry in /etc/iproute2/rt_tables file:
echo "1 admin" | sudo tee -a /etc/iproute2/rt_tables
Remove old routes
sudo ip route del 192.168.124.0/24 sudo ip route del default via 192.168.124.1
Now add the routing entries in the admin table.
sudo ip route add 192.168.124.0/24 dev eth3 src 192.168.124.106 lookup main ip route add default via 192.168.124.1 dev eth3 lookup admin
All the rules are executed in the ascending order. So, we will add rule entries above the “main” table.
ip rule add from 192.168.124.106/24 table admin ip rule add to 192.168.124.106/24 table admin ip route flush cache
Check the results
ip route list table admin ip rule show
To make these changes persistent across reboot, you can add these commands to /etc/init.d/boot.local (for SUSE Linux), or /etc/rc.d/rc.local (for Redhat, CentOS).
2.2 Netplan
- Add default route to the interface subnet.
- Add routing policy for traffic to the interface.
- Netplan accepts number as table name only.
cat /etc/netplan/50-cloud-init.yaml
# This file is generated from information provided by
# the datasource. Changes to it will not persist across an instance.
# To disable cloud-init's network configuration capabilities, write a file
# /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg with the following:
# network: {config: disabled}
network:
renderer: networkd
ethernets:
eth0:
dhcp4: yes
eth1:
dhcp4: yes
dhcp4-overrides:
route-metric: 50
eth2:
dhcp4: yes
eth3:
dhcp4: yes
dhcp4-overrides:
route-metric: 100
routing-policy:
- from: 192.168.124.0/24
table: 200
- to: 192.168.124.0/24
table: 200
routes:
- to: 0.0.0.0/0
via: 192.168.124.1
table: 200
version: 2
Journal show Logs
ls /var/log
The gnome-system-log or Gnome System Log viewer can be very useful tools to view system log files on Fedora Linux Desktop (Gnome Desktop).
Open Gnome System Log using command:
Open the terminal on Linux Fedora desktop. Execute the su -c "yum install gnome-system-log" Execute gnome-system-log
the Gnome System Log viewer you enable you to view…
/var/log/cron - the cron log file /var/log/messages - the messages log file /var/log/secure - the secure log file /var/log/Xorg.0.log - the Xorg.0.log log file
and much more ….
On Fedora 20+, we use journalctl by default. Regular files such as /var/log/messages are no longer available by default. Of course, you can install rsyslog and journalctl will generate them for you if you want. journalctl itself has many many options. For example, you can filter the log based on different criteria. You can view the current or previous boot logs using the -b flag. Here are some examples from man journalctl (Please read the man page for more detailed information on the available options):
Without arguments, all collected logs are shown unfiltered:
journalctl
With one match specified, all entries with a field matching the expression are shown:
journalctl SYSTEMDUNIT=avahi-daemon.service
If two different fields are matched, only entries matching both expressions at the same time are shown:
journalctl SYSTEMDUNIT=avahi-daemon.service _PID=28097
If two matches refer to the same field, all entries matching either expression are shown:
journalctl SYSTEMDUNIT=avahi-daemon.service SYSTEMDUNIT=dbus.service
If the separator “+” is used, two expressions may be combined in a logical OR. The following will show all messages from the Avahi service process with the PID 28097 plus all messages from the D-Bus service (from any of its processes):
journalctl SYSTEMDUNIT=avahi-daemon.service PID=28097 + _SYSTEMDUNIT=dbus.service
Show all logs generated by the D-Bus executable:
journalctl /usr/bin/dbus-daemon
Show all logs of the kernel device node /dev/sda:
journalctl /dev/sda
Show all kernel logs from previous boot:
journalctl -k -b -1
There's also the new gnome-logs package in Fedora that's a frontend to journalctl but it looks like it's only available in F21+
tar
List content:
tar -vztf ~/Downloads/eclipse-jee-kepler-SR2-linux-gtk-x86_64.tar.gz
extract gz
tar -C target_dir -xvzf ~/Downloads/eclipse-jee-kepler-SR2-linux-gtk-x86_64.tar.gz
extract bz
tar -C target_dir -xvjf ~/Downloads/eclipse-jee-kepler-SR2-linux-gtk-x86_64.tar.gz
2>&1
In a unix shell, if I want to combine stderr and stdout into the stdout stream for further manipulation, I can append the following on the end of my command:
2>&1
'head' on the output of g++:
g++ lots_of_errors 2>&1 | head
1 is stdout. 2 is stderr.
Here is one way to remember this construct (altough it is not entirely accurate): at first, 2>1 may look like a good way to redirect stderr to stdout. However, it will actually be interpreted as “redirect stderr to a file named 1”. & indicates that what follows is a file descriptor and not a filename. So the construct becomes: 2>&1.
3. Change shell
Change user shell. As normal user.
chsh -s /bin/bash
As super user
chsh -s /bin/bash username
reset Terminal colors
reset stty sane tput init tput reset
Networking
ip addr show #delete addr ip addr del 192.168.50.5/24 dev eth1 # enable ip link set eth1 up ip link set eth1 down # route table ip route show # add static route ip route add 10.10.20.0/24 via 192.168.50.100 dev eth0 ip route del 10.10.20.0/24
Add persisted static route
Fedora:
# vi /etc/sysconfig/network-scripts/route-eth0 10.10.20.0/24 via 192.168.50.100 dev eth0
Debian:
$ sudo vi /etc/network/interfaces
auto eth0
iface eth0 inet static
address 192.168.50.2
netmask 255.255.255.0
gateway 192.168.50.100
#########{Static Route}###########
up ip route add 10.10.20.0/24 via 192.168.50.100 dev eth0
Mount davfs
.tubcloud.tu-berlin.de
nextcloud
Local php python
C:\Users\Gordon>php -S 127.0.0.1:80 -t . PHP 5.4.0 Development Server started at Sun Sep 02 14:20:28 2012 Listening on 127.0.0.1:80 Document root is C:\Users\Gordon Press Ctrl-C to quit.
python SimpleHTTPServer
Recovery from Power Outage
yum history sync yum history list
[root@devnetwork fedora]# yum history list
Loaded plugins: langpacks, refresh-packagekit
ID | Command line | Date and time | Action(s) | Altered
-------------------------------------------------------------------------------
27 | history redo force-reins | 2015-01-28 17:46 | Reinstall | 1
26 | -d 0 -e 0 -y install ope | 2015-01-28 17:33 | Install | 1
25 | -d 0 -e 0 -y install ope | 2015-01-28 17:33 | Install | 1
24 | -d 0 -e 0 -y install ope | 2015-01-28 17:33 | Install | 1
23 | -d 0 -e 0 -y install ope | 2015-01-28 17:33 | Install | 1
22 | -d 0 -e 0 -y install ope | 2015-01-28 17:33 | Install | 2
21 | erase openstack-* | 2015-01-28 17:32 | Erase | 6 EE
20 | -d 0 -e 0 -y install ope | 2015-01-28 17:27 | Install | 1
19 | -d 0 -e 0 -y install ope | 2015-01-28 17:27 | Install | 1
18 | erase openvswitch* | 2015-01-28 17:26 | Erase | 1 EE
17 | update | 2015-01-28 17:04 | I, U | 196 EE
16 | -d 0 -e 0 -y install ope | 2015-01-28 17:00 | Install | 1
15 | -d 0 -e 0 -y install ope | 2015-01-28 17:00 | Install | 1 <
14 | -d 0 -e 0 -y install ope | 2015-01-28 11:06 | Install | 1 >
13 | -d 0 -e 0 -y install ope | 2015-01-28 11:06 | Install | 1
12 | -d 0 -e 0 -y install ope | 2015-01-28 11:05 | Install | 23
11 | -d 0 -e 0 -y install ntp | 2015-01-28 11:05 | Install | 2
10 | -d 0 -e 0 -y install hap | 2015-01-28 11:05 | Install | 1
9 | -d 0 -e 0 -y install ope | 2015-01-28 11:05 | Install | 1
8 | -d 0 -e 0 -y install pyt | 2015-01-28 11:04 | Install | 54
Read the fine manual page and try the yum history commands.
The redo command might not work when it thinks that the packages are already installed, but after a rollback you should be able to (re)install the group. you can use the force-reinstall option on the yum history redo command
wget scrawl website
wget -r -np -l 1 -A zip http://example.com/download/ Options meaning: -r, --recursive specify recursive download. -np, --no-parent don't ascend to the parent directory. -l, --level=NUMBER maximum recursion depth (inf or 0 for infinite). -A, --accept=LIST comma-separated list of accepted extensions.
Screen
Diff, patch merge files
ou don't need patch for this; it's for extracting changes and sending them on without the unchanged part of the file. The tool for merging two versions of a file is merge, but as @vonbrand wrote, you need the "base" file from which your two versions diverged. To do a merge without it, use diff like this: diff -DVERSION1 file1.xml file2.xml > merged.xml It will enclose each set of changes in c-style #ifdef/#ifndef, like this: #ifdef VERSION1 <stuff added to file1.xml> #endif ... #ifndef VERSION1 <stuff added to file2.xml> #endif If a line or region differs between the two files, you'll get a "conflict", which looks like this: #ifndef VERSION1 <version 1> #else /* VERSION1 */ <version 2> #endif /* VERSION1 */ So save the output in a file, and open it in an editor. Search for any places where #else comes up, and resolve them manually. Then save the file and run it through grep -v to get rid of the remaining #if and #end tags: grep -v '^#if' merged.xml | grep -v '^#endif' > clean.xml In the future, save the original version of the file. merge can give you much better results with the help of the extra information. (But be careful: merge edits one of the files in-place, unless you use -p. Read the manual).
lsof
.http://www.akadia.com/services/lsof_quickstart.txt
List deleted files
lsof -a +L1 mountpoint ... java 30255 demo 1w REG 252,0 24105963520 0 131115 /home/demo/imacatlogs/catalina.out (deleted)
See which process causes that
ps aux | grep 30255 netstat -ntlp | grep 30255 tcp6 0 0 :::50480 :::* LISTEN 30255/java
Remove (deleted) files
use lsof to find the deleted, but open, file still consuming space
lsof | grep deleted | grep etilqs_1IlrBRwsveCCxId
chrome 3446 user 128u REG 253,2 16400 2364626 /var/tmp etilqs1IlrBRwsveCCxId (deleted)
find the entry in /proc/fd/ that cooresponds to the filehandle
ls -l /proc/3446/fd/etilqs_1IlrBRwsveCCxId
lrwx------. 1 user unix 64 Feb 11 15:31 128 -> /var/tmp/etilqs_1IlrBRwsveCCxId (deleted)
now, just cat /dev/null into the fd
cat /dev/null > /proc/3446/fd/128
Note that the inode is still open, but now it's 0 length
chrome 3446 user 128u REG 253,2 0 2364626
Get streaming Firefox file
Get the process id
ps aux | grep firefox ps aux | grep firefox dang 3224 10.5 18.7 4975896 3043840 tty2 Rl+ Dec06 811:15 /usr/lib64/firefox/firefox root 10006 0.0 0.0 114332 2320 pts/0 S+ 19:51 0:00 grep --color=auto firefox dang 31850 1.3 1.7 1342864 287844 tty2 Sl+ Dec09 43:13 /usr/lib64/firefox/plugin-container /usr/lib64/flash-plugin/libflashplayer.so -greomni /usr/lib64/firefox/omni.ja -appomni /usr/lib64/firefox/browser/omni.ja -appdir /usr/lib64/firefox/browser 3224 true plugin
31850 is the process
ls -ls /proc/31850/fd
This will show the /tmp/Flash…
Alternatives
[root@dai142 gtarc_auvegos]# alternatives --config javaws There are 3 programs which provide 'javaws'. Selection Command ----------------------------------------------- * 1 /usr/java/latest/jre/bin/javaws 2 /usr/java/jdk1.8.0_66/jre/bin/javaws + 3 /usr/java/jdk1.8.0_66/bin/javaws Enter to keep the current selection[+], or type selection number: [root@dai142 gtarc_auvegos]# alternatives --remove javaws /usr/java/jdk1.8.0_66/jre/bin/javaws [root@dai142 gtarc_auvegos]# alternatives --config javaws There are 2 programs which provide 'javaws'. Selection Command ----------------------------------------------- * 1 /usr/java/latest/jre/bin/javaws + 2 /usr/java/jdk1.8.0_66/bin/javaws Enter to keep the current selection[+], or type selection number: [root@dai142 gtarc_auvegos]#
4. Disable suspend on laptop
5. Latex
Boot kernel version
Comments:
Run grubby to see a list of bootable kernels:
grubby --info=ALL | grep '^title=' | sed 's/title=//'
Imagine these are numbered 1, 2, 3, etc. Set a variable to capture the title using the sed command. This example uses
sed -n 2p
for the #2 kernel, but you could substitute 3 or whatever instead:
NEWDEFAULT=$(!! | sed -n 2p)
Check to make sure the variable is a kernel title. If not, do the above two commands again correctly, one following the other immediately.
echo ${NEWDEFAULT}
Replace the default in the GRUB defaults file:
sudo sed -i "s/GRUB_DEFAULT=.*/GRUB_DEFAULT="${NEWDEFAULT}"/"
Rewrite the GRUB configuration:
sudo grub2-mkconfig -o /boot/grub2/grub.cfg
the above rewrite command for GRUB only applies for legacy BIOS installations with MBR partition layout.
EFI with GPT layout system users should do the following instead
grub2-mkconfig -o /boot/efi/EFI/fedora/grub.cfg
Now you can reboot into the locked kernel. The above process works independently of versionlock. It uses a kernel title instead of a numbered slot, so that if kernel index order changes, the desired default should still boot.
