Commands by kerim (6)

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a function to find the fastest DNS server
http://public-dns.info gives a list of online dns servers. you need to change the country in url (br in this url) with your country code. this command need some time to ping all IP in list.

Get IPv4 of eth0 for use with scripts
Combines wgzhao's grep | awk | sed into one awk command.

Broadcast your shell thru port 5000
Doesn't work so well if you connect from windows. Linux only sends LF where windows wants CRLF. The alternative command works better with windows, however it uses script and a named pipe.

list block devices
Shows all block devices in a tree with descruptions of what they are.

Robust expansion (i.e. crash) of bash variables with a typo
By default bash expands an unbound variable to an empty string. This can be dangerous, if a critical variable name (a path prefix for example) has a typo. The -u option causes bash to treat this as an error, and the -e option causes it to exit in case of an error. These two together will make your scripts a lot safer against typos. The default behaviour can be explicitly requested using the ${NAME:-} syntax. A (less explicit) variation: #!/bin/bash -eu

Print stack trace of a core file without needing to enter gdb interactively
The pstack command prints a stack trace of running processes without needing to attach a debugger, but what about core files? The answer, of course, is to use this command. Usage: gdbbt program corefile

locate a filename, make sure it exists and display it with full details
use the locate command to find files on the system and verify they exist (-e) then display each one in full details.

search ubuntu packages to find which package contains the executable program programname
search ubuntu's remote package source repositories for a specific program to see which package contains it

Update grub menu.lst
Remove all commented lines Remove all blank lines Show the menu Up the delay so you have enough time to select a kernel Remove the quiet so you can watch the entire boot Add a rootdelay for san attached storage booting

Runs previous command replacing foo by bar every time that foo appears
To replace foo by bar, but not execute, do ^foo^bar^:p To replace all foo by bar, but not execute, do ^foo^bar^:&:p


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