Commands by igorfu

Commands by igorfu (10)

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Slow down IO heavy process

Some IO intensive process make the system unresponsive. This function periodically starts/stops a process, which hopefully releases some resources for other activities. This function is useful when ionice is not available Show Sample Output
This is sample output - yours may be different.
```
bash> cp /tmp/BIG /tmp/2 & slow $!
[1] 26494
[2] 26495
```
1

slow () { [ -n $1 ] && while ps -p $1 >/dev/null ; do kill -STOP $1; sleep 1; kill -CONT $1; sleep 1; done & }

igorfu · 2012-05-16 12:13:30 4
find and delete empty directories recursively
This is sample output - yours may be different.
0

perl -MFile::Find -e"finddepth(sub{rmdir},'.')"

igorfu · 2011-05-23 08:45:59 5
Delete empty directories

Recursively delete empty directories. Use with care.
This is sample output - yours may be different.
1

perl -MFile::Find -e"finddepth(sub{rmdir},'.')"

igorfu · 2011-05-23 08:45:34 8
Database size

Mysql command to list the disk usage of the database
This is sample output - yours may be different.
1

SELECT table_schema "Data Base Name", sum( data_length + index_length ) / 1024 / 1024 "Data Base Size in MB" FROM information_schema.TABLES GROUP BY table_schema ;

igorfu · 2011-05-23 08:42:38 5
list tomcat webapps

Tomcat webapps are often remote links
This is sample output - yours may be different.
0

ssh tomcat-server ls -l webapp-dir | grep -- '->' | awk ' { print $(NF-2) " " $(NF-1) " " $NF; }'

igorfu · 2011-05-23 08:38:28 4
Block an IP address

Thanks to http://www.cyberciti.biz/faq/how-do-i-block-an-ip-on-my-linux-server/
This is sample output - yours may be different.
-1

iptables -A INPUT -s 65.55.44.100 -j DROP

igorfu · 2011-05-23 08:32:47 5
Send an email using the mutt email client

It's very similar to this thread: http://www.commandlinefu.com/commands/view/4317/send-a-local-file-via-email mutt your@email_address.com -s "Message Subject Here" -a attachment.jpg </dev/null
This is sample output - yours may be different.
-2

M=bob@example.com; echo "Email message" | mutt -s "Email Subject" $M

igorfu · 2011-05-23 08:31:14 12
Restore accents in vi & others

French uses accents (???...) which may be badly displayed on computers with the wrong default character set. This command may help (sometimes)
This is sample output - yours may be different.
-1

LANG=fr_FR@euro

igorfu · 2011-05-23 08:27:22 4
Call remote web service

Use curl to invoke remote web service, where the file 'XML' is the soap payload
This is sample output - yours may be different.
-1

curl -D - -X POST -H 'Content-type: text/xml' -d @XML http://remote_server:8080/web-service/soap/WSName

igorfu · 2011-05-23 08:25:24 4
Install a remote RPM
This is sample output - yours may be different.
-1

sudo rpm -if "http://rpm_server/rpm_repo/this-app.rpm"

igorfu · 2011-05-23 08:19:15 7

What's this?

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Which processes are listening on a specific port (e.g. port 80)

swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Backup with versioning

Apart from an exact copy of your recent contents, also keep all earlier versions of files and folders that were modified or deleted. Inspired by EVACopy http://evacopy.sourceforge.net

summarize a list of IP addresses, verifying IP address and giving counts for each IP found

Working with lists of IP addresses it is sometimes useful to summarize a count of how many times an IP address appears in the file. This example, summarizeIP, uses another function "verifyIP" previously defined in commandlinefu.com to ensure only valid IP addresses get counted. The summary list is presented in count order starting with highest count.

Triple monitoring in screen

This command starts screen with 'htop', 'nethogs' and 'iotop' in split-screen. You have to have these three commands (of course) and specify the interface for nethogs - mine is wlan0, I could have acquired the interface from the default route extending the command but this way is simpler. htop is a wonderful top replacement with many interactive commands and configuration options. nethogs is a program which tells which processes are using the most bandwidth. iotop tells which processes are using the most I/O. The command creates a temporary "screenrc" file which it uses for doing the triple-monitoring. You can see several examples of screenrc files here: http://www.softpanorama.org/Utilities/Screen/screenrc_examples.shtml

back ssh from firewalled hosts

host B (you) redirects a modem port (62220) to his local ssh. host A is a remote machine (the ones that issues the ssh cmd). once connected port 5497 is in listening mode on host B. host B just do a ssh 127.0.0.1 -p 5497 -l user and reaches the remote host'ssh. This can be used also for vnc and so on.

check open ports without netstat or lsof

Create a backup of file being edited while using vi

At the start of a vi session and *before* saving any changes use ":!cp % %-" to make a backup of the current file being edited. example: vi /data/some/long/path/file :!cp% %- creates /data/some/long/path/file-

Arguments too long

set wallpaper on windowmaker in one line

set directly the wallpaper on windowmaker , use this command with display of imagemagick :)

Convert seconds to [DD:][HH:]MM:SS

Converts any number of seconds into days, hours, minutes and seconds. sec2dhms() { declare -i SS="$1" D=$(( SS / 86400 )) H=$(( SS % 86400 / 3600 )) M=$(( SS % 3600 / 60 )) S=$(( SS % 60 )) [ "$D" -gt 0 ] && echo -n "${D}:" [ "$H" -gt 0 ] && printf "%02g:" "$H" printf "%02g:%02g\n" "$M" "$S" }

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