Commands by mahendra (1)

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A command to post a message to Twitter that includes your geo-location and a short URL.
A command to post a message to Twitter that includes your geo-location and a short URL. The link shortening service is provide by TinyURL, the geo-location service is provided by HostIP and the IP address lookup service is provided by AppSpot. This is an upgrade of an of one of my previous contributions: http://tinyurl.com/yd2xtzv.

Go to the next sibling directory in alphabetical order
Sometimes you have to browse your way through a lot of sub-directories. This command cd to the next sub-directory in alphabetical order. For example, if you have the directories "lectures/01-intro", "lectures/02-basic", "lectures/03-advanced" and so on, and your PWD is "02-basic", it jumps to "03-advanced".

Define an alias with a correct completion
In Bash, when defining an alias, one usually loses the completion related to the function used in that alias (that completion is usually defined in /etc/bash_completion using the complete builtin). It's easy to reuse the work done for that completion in order to have smart completion for our alias. That's what is done by this command line (that's only an example but it may be very easy to reuse). Note 1 : You can use given command line in a loop "for old in apt-get apt-cache" if you want to define aliases like that for many commands. Note 2 : You can put the output of the command directly in your .bashrc file (after the ". /etc/bash_completion") to always have the alias and its completion

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" }

VIM: when Ctrl-D and Ctrl-U only scroll one line, reset to default
Resets the scroll parameter to the default (half the rows in the current window). The scroll parameter can be inadvertently set to 1, e..g., if you type '1 Ctrl-D' or '1 Ctrl-U' in normal mode.

Filter the output of a file continously using tail and grep

The fastest remote directory rsync over ssh archival I can muster (40MB/s over 1gb NICs)
This creates an archive that does the following: rsync:: (Everyone seems to like -z, but it is much slower for me) -a: archive mode - rescursive, preserves owner, preserves permissions, preserves modification times, preserves group, copies symlinks as symlinks, preserves device files. -H: preserves hard-links -A: preserves ACLs -X: preserves extended attributes -x: don't cross file-system boundaries -v: increase verbosity --numeric-ds: don't map uid/gid values by user/group name --delete: delete extraneous files from dest dirs (differential clean-up during sync) --progress: show progress during transfer ssh:: -T: turn off pseudo-tty to decrease cpu load on destination. -c arcfour: use the weakest but fastest SSH encryption. Must specify "Ciphers arcfour" in sshd_config on destination. -o Compression=no: Turn off SSH compression. -x: turn off X forwarding if it is on by default. Flip: rsync -aHAXxv --numeric-ids --delete --progress -e "ssh -T -c arcfour -o Compression=no -x" [source_dir] [dest_host:/dest_dir]

Synchronize date and time with a server over ssh
Set Remote Server Date using Local Server Time (push)

MSDOS command to check existance of command and exit batch if failed
This is a command to be used inside of MS-DOS batch files to check existence of commands as preconditions before actual batch processing can be started. If the command is found, batch script continues execution. If not, a message is printed on screen, script then waits for user pressing a key and exits. An error message of the command itself is suppressed for clarity purpose.

make 100 directories with leading zero, 001...100, using bash3.X


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