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Commands tagged /dev/null from sorted by
Terminal - Commands tagged /dev/null - 7 results
alias ...='while read line; do echo -n "."; done && echo ""'
alias ...="awk '{fflush(); printf \".\"}' && echo \"\""
2014-02-22 22:20:22
User: lgarron
Functions: alias
7

If you're running a command with a lot of output, this serves as a simple progress indicator.

This avoids the need to use `/dev/null` for silencing. It works for any command that outputs lines, updates live (`fflush` avoids buffering), and is simple to understand.

for line in `cat $file`; do firefox -new-tab "$line" & 2>/dev/null; sleep 1; done
2011-11-12 13:47:24
User: hamsolo474
Functions: sleep
2

this will open a new tab in firefox for every line in a file

the sleep is removable but i found that if you have a large list of urls 50+, and no sleep, it will try to open all the urls at once and this will cause them all to load a lot slower, also depending on the ram of your system sleep gives you a chance to close the tabs before they overload your ram, removing & >2/dev/null will yield unpredictable results.

svnradd() { for i in $1/*;do if [ -e "$i" ];then if [ -d "$i" ];then svn add $i;svnradd $i;else svn add $i;fi; fi;done }
2011-02-16 03:33:57
User: lkjoel
0

This will recursively add files/directories in SVN.

Usage:

svnradd yourfile

or

svnradd yourdirectory

then:

svn commit

Notice: It might not work properly, and not all files could get added.

Since there is a limit on characters, I couldn't add failure/success notices.

If you want failure/success notices, download Terminal Enhancements (http://tenhancements.tk/ )

It is included on Base Features

alias head='head -n $((${LINES:-`tput lines 2>/dev/null||echo -n 12`} - 2))'
26

Run the alias command, then issue

ps aux | head

and resize your terminal window (putty/console/hyperterm/xterm/etc) then issue the same command and you'll understand.

${LINES:-`tput lines 2>/dev/null||echo -n 12`}

Insructs the shell that if LINES is not set or null to use the output from `tput lines` ( ncurses based terminal access ) to get the number of lines in your terminal. But furthermore, in case that doesn't work either, it will default to using the deafault of 12 (-2 = 10).

The default for HEAD is to output the first 10 lines, this alias changes the default to output the first x lines instead, where x is the number of lines currently displayed on your terminal - 2. The -2 is there so that the top line displayed is the command you ran that used HEAD, ie the prompt.

Depending on whether your PS1 and/or PROMPT_COMMAND output more than 1 line (mine is 3) you will want to increase from -2. So with my prompt being the following, I need -7, or - 5 if I only want to display the commandline at the top. ( http://www.askapache.com/linux-unix/bash-power-prompt.html )

275MB/748MB

[7995:7993 - 0:186] 06:26:49 Thu Apr 08 [askapache@n1-backbone5:/dev/pts/0 +1] ~

In most shells the LINES variable is created automatically at login and updated when the terminal is resized (28 linux, 23/20 others for SIGWINCH) to contain the number of vertical lines that can fit in your terminal window. Because the alias doesn't hard-code the current LINES but relys on the $LINES variable, this is a dynamic alias that will always work on a tty device.

pv /dev/zero|ssh $host 'cat > /dev/null'
2010-01-06 20:40:51
User: opertinicy
Functions: ssh
Tags: ssh pv /dev/null
11

connects to host via ssh and displays the live transfer speed, directing all transferred data to /dev/null

needs pv installed

Debian: 'apt-get install pv'

Fedora: 'yum install pv' (may need the 'extras' repository enabled)

( trap '' 1; ( nice -n 19 sleep 2h && command rm -v -rf /garbage/ &>/dev/null && trap 1 ) & )
2

Check out the usage of 'trap', you may not have seen this one much. This command provides a way to schedule commands at certain times by running them after sleep finishes sleeping. In the example 'sleep 2h' sleeps for 2 hours. What is cool about this command is that it uses the 'trap' builtin bash command to remove the SIGHUP trap that normally exits all processes started by the shell upon logout. The 'trap 1' command then restores the normal SIGHUP behaviour.

It also uses the 'nice -n 19' command which causes the sleep process to be run with minimal CPU.

Further, it runs all the commands within the 2nd parentheses in the background. This is sweet cuz you can fire off as many of these as you want. Very helpful for shell scripts.