History usually only gives the command number and the command. This will add a timestamp to the history file. Note: this will only put the correct timestamp on commands used after the export is done. You may want to put this in your .bashrc Show Sample Output
Very useful in shell scripts because you can run a task nicely in the background using job-control and output progress until it completes.
Here's an example of how I use it in backup scripts to run gpg in the background to encrypt an archive file (which I create in this same way). $! is the process ID of the last run command, which is saved here as the variable PI, then sleeper is called with the process id of the gpg task (PI), and sleeper is also specified to output : instead of the default . every 3 seconds instead of the default 1. So a shorter version would be sleeper $!;
The wait is also used here, though it may not be needed on your system.
echo ">>> ENCRYPTING SQL BACKUP"
gpg --output archive.tgz.asc --encrypt archive.tgz 1>/dev/null &
PI=$!; sleeper $PI ":" 3; wait $PI && rm archive.tgz &>/dev/null
Previously to get around the $! not always being available, I would instead check for the existance of the process ID by checking if the directory /proc/$PID existed, but not everyone uses proc anymore. That version is currently the one at http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html but I plan on upgrading to this new version soon.
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When browsing java source code (for example) it's really annoying having to type the first letter of the package when there is only one package in the subdir. man bash for more info about FIGNORE
when working with many machines in a computer lab need to know the IP addr is very large, this is a simplistic solution to make things easier Show Sample Output
When you use a "for" construct, it cycles on every word. If you want to cycle on a line-by-line basis (and, well, you can't use xargs -n1 :D), you can set the IFS variable to . Show Sample Output
Each shell function has its own summary line, as a comment. If there are multiple shell functions with the same name, the function with the highest number of votes is put into the file. Note: added 'grep -v' to the end of the pipeline, to eliminate extraneous lines containing only '--'. Thanks to matthewbauer for pointing this out.
I put that line in my .bash_profile (OS X) and .bashrc (Linux). Here is a summary of what the \char means: n=new line, u=user name, h=host, !=history number, w=current work directory The \[\e[32m\] sequence set the text to bright green and \[\e[0m\] returns to normal color. For more information on what you can set in your bash prompt, google 'bash prompt'
for the change stay in your history file , export command by writing it into your .bashrc Show Sample Output
Date-time format: YYYY-MM-DD HH:MM:SS Show Sample Output
Useful in root's .profile - will auto-logout after TMOUT seconds of inactivity. Close after `seconds` inactive. export TMOUT=seconds (unefunge)
It colors the machine name and current directory different colors for easy viewing.
Don't track in history commands starting with whitespace. Moreover ignore duplicates from history. To be set in .bashrc ex. $ export HISTCONTROL=ignoreboth $ echo antani $ history|grep -c antani
This one eliminates the additional backslash at the end (which is not necessary) Show Sample Output
This will cause bash to fix a garbled terminal before the prompt is printed. For example, if you cat a file with nonprintable character sequences, the terminal sometimes ends up in a mode where it only prints line drawing characters. This sequence will return the terminal to the standard character set after every command.
works on all unices. Show Sample Output
On systems where your home directory is shared across different machines, your bash history will be global, rather than being a separate history per machine. This setting in your .bashrc file will ensure that each machine has its own history file.
Works on real time clock, unix time based, decrementing the actual time from initial time saved in an environment variable exported to child process inside watch Shows elapsed time from start of script in hh:mm:ss format Non afected by system slow down due to the use of date.
blue and yellow colored bash prompt for a Hanukkah celebration on your box
Say if you're logged into a remote system via ssh and this system has an x window system, but yet you still want a screen shot of what's going on graphically. This will do it for you. :-)
If the return code from the last command was greater than zero, colour part of your prompt red. The commands give a prompt like this: [user current_directory]$ After an error, the "[user" part is automatically coloured red. Tested using bash on xterm and terminal. Place in your .bashrc or .bash_profile.
<space>secret_command;export HISTCONTROL=
This will make "secret_command" not appear in "history" list.
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