Commands using uniq (255)

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Schedule Nice Background Commands That Won't Die on Logout - Alternative to nohup and at
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.

Set access and modification timestamps of a file using another one as reference
atime and mtime timestamps of $FILE2 is changed according to the ones of $FILE1. If $FILE2 doesn't exist is created.

Swap a file or dir with quick resotre
This lets you replace a file or directory and quickly revert if something goes wrong. For example, the current version of a website's files are in public_html. Put a new version of the site in public_html~ and execute the command. The names are swapped. If anything goes wrong, execute it again (up arrow or !!).

print all characters of a file using hexdump
'od -c' works like 'hexdump -c' but is available on other operating systems that don't ship with hexdump (e.g. solaris).

copy partition table from /dev/sda to /dev/sdb

remove audio trac from a video file
create a copy of a video file without the audio tracs

exit without saving history
this exits bash without saving the history. unlike explicitly disabling the history in some way, this works anywhere, and it works if you decide *after* issuing the command you don't want logged, that you don't want it logged ... $$ ( or ${$} ) is the pid of the current bash instance this also works perfectly in shells that don't have $$ if you do something like $ kill -9 `readlink /proc/self`

Sorted list of established destination connections
no need grep. its redundant when awk is present.

Process command output line by line in a while loop
This snippet allows to process the output of any bash command line by line.

Displays the number of processes per state


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