If you have used bash for any scripting, you've used the date command alot. It's perfect for using as a way to create filename's dynamically within aliases,functions, and commands like below.. This is actually an update to my first alias, since a few commenters (below) had good observations on what was wrong with my first command.
# creating a date-based ssh-key for askapache.github.com
ssh-keygen -f ~/.ssh/`date +git-$USER@$HOSTNAME-%m-%d-%g` -C 'webmaster@askapache.com'
# /home/gpl/.ssh/git-gplnet@askapache.github.com-04-22-10
# create a tar+gzip backup of the current directory
tar -czf $(date +$HOME/.backups/%m-%d-%g-%R-`sed -u 's/\//#/g' <<< $PWD`.tgz) .
# tar -czf /home/gpl/.backups/04-22-10-01:13-#home#gpl#.rr#src.tgz .
I personally find myself having to reference
date --help
quite a bit as a result. So this nice alias saves me a lot of time. This is one bdash mofo. Works in sh and bash (posix), but will likely need to be changed for other shells due to the parameter substitution going on.. Just extend the sed command, I prefer sed to pretty much everything anyways.. but it's always preferable to put in the extra effort to go for as much builtin use as you can. Otherwise it's not a top one-liner, it's a lazyboy recliner.
Here's the old version:
alias dateh='date --help|sed "/^ *%%/,/^ *%Z/!d;s/ \+/ /g"|while read l;do date "+ %${l/% */}_${l/% */}_${l#* }";done|column -s_ -t'
This trick from my [ http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html bash_profile ]
Show Sample Output
I needed a way to search all files in a web directory that contained a certain string, and replace that string with another string. In the example, I am searching for "askapache" and replacing that string with "htaccess". I wanted this to happen as a cron job, and it was important that this happened as fast as possible while at the same time not hogging the CPU since the machine is a server. So this script uses the nice command to run the sh shell with the command, which makes the whole thing run with priority 19, meaning it won't hog CPU processing. And the -P5 option to the xargs command means it will run 5 separate grep and sed processes simultaneously, so this is much much faster than running a single grep or sed. You may want to do -P0 which is unlimited if you aren't worried about too many processes or if you don't have to deal with process killers in the bg. Also, the -m1 command to grep means stop grepping this file for matches after the first match, which also saves time. Show Sample Output
poorman's ifstat using just sh and awk. You must change "eth0" with your interface's name. Show Sample Output
I love this function because it tells me everything I want to know about files, more than stat, more than ls. It's very useful and infinitely expandable.
find $PWD -maxdepth 1 -printf '%.5m %10M %#9u:%-9g %#5U:%-5G [%AD | %TD | %CD] [%Y] %p\n' | sort -rgbS 50%
00761 drwxrw---x askapache:askapache 777:666 [06/10/10 | 06/10/10 | 06/10/10] [d] /web/cg/tmp
The key is:
# -printf '%.5m %10M %#9u:%-9g %#5U:%-5G [%AD | %TD | %CD] [%Y] %p\n'
which believe it or not took me hundreds of tweaking before I was happy with the output.
You can easily use this within a function to do whatever you want.. This simple function works recursively if you call it with -r as an argument, and sorts by file permissions.
lsl(){ O="-maxdepth 1";sed -n '/-r/!Q1'<<<$@ &&O=;find $PWD $O -printf '%.5m %10M %#9u:%-9g %#5U:%-5G [%AD | %TD | %CD] [%Y] %p\n'|sort -rgbS 50%; }
Personally I'm using this function because:
lll () { local a KS="1 -r -g"; sed -n '/-sort=/!Q1' <<< $@ && KS=`sed 's/.*-sort=\(.*\)/\1/g'<<<$@`;
find $PWD -maxdepth 1 -printf '%.5m %10M %#9u:%-9g %#5U:%-5G [%AD | %TD | %CD] [%Y] %p\n'|sort -k$KS -bS 50%; }
# i can sort by user
lll -sort=3
# or sort by group reversed
lll -sort=4 -r
# and sort by modification time
lll -sort=6
If anyone wants to help me make this function handle multiple dirs/files like ls, go for it and I would appreciate it.. Something very minimal would be awesome.. maybe like:
for a; do lll $a; done
Note this uses the latest version of GNU find built from source, easy to build from gnu ftp tarball. Taken from my http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html
Show Sample Output
outputs a f=220Hz guitar string sound (fifth string A) needs ALSA
cat mod_log_config.c | shmore
or
shmore < mod_log_config.c
Most pagers like less, more, most, and others require additional processes to be loaded, additional cpu time used, and if that wasn't bad enough, most of them modify the output in ways that can be undesirable.
What I wanted was a "more" pager that was basically the same as running:
cat file
Without modifying the output and without additional processes being created, cpu used, etc. Normally if you want to scroll the output of cat file without modifying the output I would have to scroll back my terminal or screen buffer because less modifies the output.
After looking over many examples ranging from builtin cat functions created for csh, zsh, ksh, sh, and bash from the 80's, 90s, and more recent examples shipped with bash 4, and after much trial and error, I finally came up with something that satisifed my objective. It automatically adjusts to the size of your terminal window by using the LINES variable (or 80 lines if that is empty) so
This is a great function that will work as long as your shell works, so it will work just find if you are booted in single user mode and your /usr/bin directory is missing (where less and other pagers can be). Using builtins like this is fantastic and is comparable to how busybox works, as long as your shell works this will work.
One caveat/note: I always have access to a color terminal, and I always setup both the termcap and the terminfo packages for color terminals (and/or ncurses and slang), so for that reason I stuck the
tput setab 4; tput setaf 7
command at the beginning of the function, so it only runs 1 time, and that causes the -- SHMore -- prompt to have a blue background and bright white text.
This is one of hundreds of functions I have in my http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html">.bash_profile at http://www.askapache.com/">AskApache.com, but actually won't be included till the next update.
If you can improve this in any way at all please let me know, I would be very grateful! ( Like one thing I want is to be able to continue to the next screen by pressing any key instead of now having to press enter to continue)
Show Sample Output
Once you get into advanced/optimized scripts, functions, or cli usage, you will use the sort command alot. The options are difficult to master/memorize however, and when you use sort commands as much as I do (some examples below), it's useful to have the help available with a simple alias. I love this alias as I never seem to remember all the options for sort, and I use sort like crazy (much better than uniq for example).
# Sorts by file permissions
find . -maxdepth 1 -printf '%.5m %10M %p\n' | sort -k1 -r -g -bS 20%
00761 drwxrw---x ./tmp
00755 drwxr-xr-x .
00701 drwx-----x ./askapache-m
00644 -rw-r--r-- ./.htaccess
# Shows uniq history fast
history 1000 | sed 's/^[0-9 ]*//' | sort -fubdS 50%
exec bash -lxv
export TERM=putty-256color
Taken from my http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html
Show Sample Output
This shows every bit of information that stat can get for any file, dir, fifo, etc. It's great because it also shows the format and explains it for each format option.
If you just want stat help, create this handy alias 'stath' to display all format options with explanations.
alias stath="stat --h|sed '/Th/,/NO/!d;/%/!d'"
To display on 2 lines:
( F=/etc/screenrc N=c IFS=$'\n'; for L in $(sed 's/%Z./%Z\n/'<<<`stat --h|sed -n '/^ *%/s/^ *%\(.\).*$/\1:%\1/p'`); do G=$(echo "stat -$N '$L' \"$F\""); eval $G; N=fc;done; )
For a similarly powerful stat-like function optimized for pretty output (and can sort by any field), check out the "lll" function
http://www.commandlinefu.com/commands/view/5815/advanced-ls-output-using-find-for-formattedsortable-file-stat-info
From my .bash_profile ->
http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html
Show Sample Output
If a tmux session is already running attach it, otherwise create a new one. Useful if you often forget about running tmuxes (or just don't care)
url can be like any one of followings:
url="MejbOFk7H6c"
url="http://youtu.be/MejbOFk7H6c"
url="https://youtube.com/watch?feature=player_embedded&v=MejbOFk7H6c#t"
url="//www.youtube.com/v/MejbOFk7H6c?hl=ru_RU&version=3&rel=0"
url="http://www.youtube.com/embed/MejbOFk7H6c?feature=player_embedded"
If url mismatching, whole url will be returned.
Show Sample Output
If you're only using -m or -k, you will need to remember they are either in Megabyte or kilobyte forms. So by using -B, it gives you the unit of the size measurement, which helps you from reading the result faster. You can try with -B K as well. Show Sample Output
Alternatively,
ls -F | grep /\$
but will break on directories containing newlines. Or the safe, POSIX sh way (but will miss dotfiles):
for i in *; do test -d "./$i" && printf "%s\n" "$i"; done
This will list the files in a directory, then zip each one with the original filename individually. video1.wmv -> video1.zip video2.wmv -> video2.zip This was for zipping up large amounts of video files for upload on a Windows machine.
Undocumented syntax, but should work on every shell. It'll list all directories in the current one. Change `*/` into globbing `**/` for recursivity. Show Sample Output
Also detaches session if attached from somewhere else.
Replace
'/tmp/file 1.txt' '/tmp/file 2.jpg'
with
"$NAUTILUS_SCRIPT_SELECTED_FILE_PATHS"
for Nautilus script
Or with
%F
for Thunar action
If you linking the symlinks itself, but want to link to source files instead of symlinks, use
"`readlink -m "$i"`"
instead of
"$i"
like this:
for i in '/tmp/file 1.txt' '/tmp/file 2.jpg'; do ln -s "`readlink -m "$i"`" "$i LINK"; done
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Show Sample Output
If a session with named the same as your username already exists, then attach to it, otherwise create it
The 'rename' command with the first argument as "'s/\.//'" and the second argument as "" will remove the specified extension from the filenames.
Accepts multiple files via logs...
. Substitute "text to grep" for your search string.
If you want to alias this, you could do something like this:
alias parse-logs='awk "/$1/{print \$1}" ${@[@]:1} | sort -n | uniq -c | sort -rn | head -n 100'
This command will use grep to read the shortcut (which in the above examle is file.url), and filter out all but the only important line, which contains the website URL, and some extra characters that will need to be removes (for example, URL=http://example.com). The cut command is then used to get rid of the URL= at the beginning. The output is then piped into Firefox, which should interpret the it as a web URL to be opened. Of course, you can replace Firefox with any other broswer. Tested in bash and sh.
Allows you to have a list of the domains on the server.
commandlinefu.com is the place to record those command-line gems that you return to again and again. That way others can gain from your CLI wisdom and you from theirs too. All commands can be commented on, discussed and voted up or down.
Every new command is wrapped in a tweet and posted to Twitter. Following the stream is a great way of staying abreast of the latest commands. For the more discerning, there are Twitter accounts for commands that get a minimum of 3 and 10 votes - that way only the great commands get tweeted.
» http://twitter.com/commandlinefu
» http://twitter.com/commandlinefu3
» http://twitter.com/commandlinefu10
Use your favourite RSS aggregator to stay in touch with the latest commands. There are feeds mirroring the 3 Twitter streams as well as for virtually every other subset (users, tags, functions,…):
Subscribe to the feed for: