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May 19, 2015 - A Look At The New Commandlinefu
I've put together a short writeup on what kind of newness you can expect from the next iteration of clfu. Check it out here.
March 2, 2015 - New Management
I'm Jon, I'll be maintaining and improving clfu. Thanks to David for building such a great resource!

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Commands using eval from sorted by
Terminal - Commands using eval - 46 results
getarray(){ a=$1;b="${a[$2]}";eval "c=$b";echo "${c[$3]}";return 0;};a[0]="( a b c )";a[1]="( d e f )";getarray a 1 2
l=10;for((i=0;i<$l;i++));do eval "a$i=($(pv=1;v=1;for((j=0;j<$l;j++));do [ $i -eq 0 -o $j -eq 0 ]&&{ v=1 && pv=1; }||v=$((pv+a$((i-1))[$((j))]));echo -n "$v ";pv=$v;done;));";eval "echo \"\${a$i[@]}\"";done | column -t;
to() { eval dir=\$$1; cd "$dir"; }
2010-10-15 13:40:35
User: hfs
Functions: cd eval

Set a bookmark as normal shell variable


To go there

to p

This saves one "$" and is faster to type ;-) The variable is still useful as such:

vim $p/<TAB>

will expand the variable (at least in bash) and show a list of files to edit.

If setting the bookmarks is too much typing you could add another function

bm() { eval $1=$(pwd); }

then bookmark the current directory with

bm p
marbles () { c=''; for i in $(seq $1); do c+='{b,r}'; done; x=$(eval echo $c); p=''; for i in $(seq $2); do p+='b*r'; done; y=$(grep -wo "${p}b*" <<< $x); wc -l <<< "$y"; grep -vc 'rr' <<< "$y"; }
2010-08-27 23:04:33
User: quintic
Functions: echo eval grep seq wc

Suppose you have 11 marbles, 4 of which are red, the rest being blue. The marbles are indistinguishable, apart from colour. How many different ways are there to arrange the marbles in a line? And how many ways are there to arrange them so that no two red marbles are adjacent?

There are simple mathematical solutions to these questions, but it's also possible to generate and count all possibilities directly on the command line, using little more than brace expansion, grep and wc!

The answer to the question posed above is that there are 330 ways of arranging the marbles in a line, 70 of which have no two red marbles adjacent. See the sample output.

To follow the call to marbles 11 4: after c=''; for i in $(seq $1); do c+='{b,r}'; done;, $c equals {b,r}{b,r}{b,r}{b,r}{b,r}{b,r}{b,r}{b,r}{b,r}{b,r}{b,r}

After x=$(eval echo $c), and brace expansion, $x equals bbbbbbbbbbb bbbbbbbbbbr ... rrrrrrrrrrb rrrrrrrrrrr, which is all 2^11 = 2048 strings of 11 b's and r's.

After p=''; for i in $(seq $2); do p+='b*r'; done;, $p equals b*rb*rb*rb*r

Next, after y=$(grep -wo "${p}b*"

Finally, grep -vc 'rr'

sudo ls -l $(eval echo "/proc/{$(echo $(pgrep java)|sed 's/ /,/')}/fd/")|grep log|sed 's/[^/]* //g'|xargs -r tail -f
2010-07-30 18:20:00
User: vutcovici
Functions: echo eval grep ls sed sudo tail xargs

Tail all logs that are opened by all java processes. This is helpful when you are on a new environment and you do not know where the logs are located. Instead of java you can put any process name. This command does work only for Linux.

The list of all log files opened by java process:

sudo ls -l $(eval echo "/proc/{$(echo $(pgrep java)|sed 's/ /,/')}/fd/")|grep log|sed 's/[^/]* //g'
rp() { local p; eval p=":\$$1:"; export $1=${p//:$2:/:}; }; ap() { rp "$1" "$2"; eval export $1=\$$1$2; }; pp() { rp "$1" "$2"; eval export $1=$2:\$$1; }
2010-07-15 18:52:01
User: cout
Functions: eval export

I used to do a lot of path manipulation to set up my development environment (PATH, LD_LIBRARY_PATH, etc), and one part of my environment wasn't always aware of what the rest of the environment needed in the path. Thus resetting the entire PATH variable wasn't an option; modifying it made sense.

The original version of the functions used sed, which turned out to be really slow when called many times from my bashrc, and it could take up to 10 seconds to login. Switching to parameter substitution sped things up significantly.

The commands here don't clean up the path when they are done (so e.g. the path gets cluttered with colons). But the code is easy to read for a one-liner.

The full function looks like this:

remove_path() { eval PATHVAL=":\$$1:" PATHVAL=${PATHVAL//:$2:/:} # remove $2 from $PATHVAL PATHVAL=${PATHVAL//::/:} # remove any double colons left over PATHVAL=${PATHVAL#:} # remove colons from the beginning of $PATHVAL PATHVAL=${PATHVAL%:} # remove colons from the end of $PATHVAL export $1="$PATHVAL" } append_path() { remove_path "$1" "$2" eval PATHVAL="\$$1" export $1="${PATHVAL}:$2" } prepend_path() { remove_path "$1" "$2" eval PATHVAL="\$$1" export $1="$2:${PATHVAL}" }

I tried using regexes to make this into a cleaner one-liner, but remove_path ended up being cryptic and not working as well:

rp() { eval "[[ ::\$$1:: =~ ^:+($2:)?((.*):$2:)?(.*):+$ ]]"; export $1=${BASH_REMATCH[3]}:${BASH_REMATCH[4]}; };
read -p "enter url:" a ; w3m -dump $a > /dev/shm/e1q ; less /dev/shm/e1q ; read -p "save file as text (y/n)?" b ; if [ $b = "y" ] ; then read -p "enter path with filename:" c && touch $(eval echo "$c") ; mv /dev/shm/e1q $(eval echo "$c") ; fi ; echo DONE
2010-07-13 22:36:38
User: LinuxMan
Functions: c++ echo eval less mv read touch

Thanks th John_W for suggesting the fix allowing ~/ to be used when saving a directory.


Type in a url, it will show a preview of what the file will look like when saved, then asks if you want to save the preview and where you want to save it. Great for grabbing the latest commandlinefu commands without a full web browser or even a GUI. Requires: w3m

vimlint(){ eval $(xmllint --noout "$1" 2>&1 | awk -F: '/parser error/{print "vim \""$1"\" +"$2; exit}'); }
2010-06-23 15:55:02
User: putnamhill
Functions: awk eval

Validate a file using xmllint. If there are parser errors, edit the file in vim at the line of the first error.

gopyrit () { if [ $# -lt 1 ]; then echo $0 '< list of ESSIDs >'; return -1; fi; for i in "$@"; do pyrit -e $i create_essid && pyrit batch; done; pyrit eval }
2010-06-19 01:11:00
User: meathive
Functions: echo eval return

This command will automate the creation of ESSIDs and batch processing in pyrit. Give it a list of WPA/WPA2 access points you're targeting and it'll import those ESSIDs and pre-compute the potential password hashes for you, assuming you've got a list of passwords already imported using:

pyrit -i dictionary import_passwords

Once the command finishes, point pyrit to your packet capture containing a handshake with the attack_db module. Game over.

inplace() { eval F=\"\$$#\"; "$@" > "$F".new && mv -f "$F".new "$F"; }
2010-04-09 11:36:31
User: inof
Functions: eval mv

Some commands (such as sed and perl) have options to support in-place editing of files, but many commands do not. This shell function enables any command to change files in place. See the sample output for many examples.

The function uses plain sh syntax and works with any POSIX shell or derivative, including zsh and bash.

cmd=$(wget -qO- "http://www.m-w.com/dictionary/$(echo "$@"|tr '[A-Z]' '[a-z]')" | sed -rn "s#return au\('([^']+?)', '([^'])[^']*'\);.*#\nwget -qO- http://cougar.eb.com/soundc11/\2/\1 | aplay -q#; s/[^\n]*\n//p"); [ "$cmd" ] && eval "$cmd" || exit 1
2010-03-12 13:56:41
User: hackerb9
Functions: eval exit sed wget

Looks up a word on merriam-webster.com, does a screen scrape for the FIRST audio pronunciation and plays it.

USAGE: Put this one-liner into a shell script (e.g., ~/bin/pronounce) and run it from the command line giving it the word to say:

pronounce lek

If the word isn't found in merriam-webster, no audio is played and the script returns an error value. However, M-W is a fairly complete dictionary (better than howjsay.com which won't let you hear how to pronounce naughty words).

ASSUMPTIONS: GNU's sed (which supports -r for extended regular expressions) and Linux's aplay. Aplay can be replaced by any program that can play .WAV files from stdin.

KNOWN BUGS: only the FIRST pronunciation is played, which is problematic if you wanted a particular form (plural, adjectival, etc) of the word. For example, if you run this:

pronounce onomatopoetic

you'll hear a voice saying "onomatopoeia".

Playing the correct form of the word is possible, but doing so might make the screen scraper even more fragile than it already is. (The slightest change to the format of m-w.com could break it).

eval `ssh-agent`; screen
2010-03-07 14:58:54
User: mechmind
Functions: eval

When you start screen as `ssh-agent screen`, agent will die after detatch.

If you don't want to take care about files when stored agent's pid/socket/etc, you have to use this command.

Split() { eval "$1=( \"$(echo "${!1}" | sed "s/$2/\" \"/g")\" )"; }
2010-02-08 17:41:59
User: frans
Functions: eval

It works as a method applicated to a variable, converts the string variable into an array

eval $(curl -s http://www.commandlinefu.com/commands/matching/external/ZXh0ZXJuYWw=/sort-by-votes/plaintext|sed -n '/^# Get your external IP address$/{n;p;q}')
2009-11-04 16:58:31
User: jgc
Functions: eval sed

This command uses the top voted "Get your external IP" command from commandlinefu.com to get your external IP address.

Use this and you will always be using the communities favourite command.

This is a tongue-in-cheek entry and not recommended for actual usage.

perl -we 'my $regex = eval {qr/.*/}; die "$@" if $@;'
2009-10-13 21:50:47
User: tlacuache
Functions: eval perl

Place the regular expression you want to validate between the forward slashes in the eval block.

perl -e '$x = []; push @$x, eval { $x = 1; return $x = 1; }'
2009-10-07 22:42:18
User: dstahlke
Functions: eval perl return

It is not easy to make perl give a segfault, but this does it. This is a known issue but apparently not easy to fix. This is completely useless except for showing people that perl is not bullet-proof.

eval $(sed -n "s/^d[^D]*DB_\([NUPH]\)[ASO].*',[^']*'\([^']*\)'.*/_\1='\2'/p" wp-config.php) && mysqldump --opt --add-drop-table -u$_U -p$_P -h$_H $_N | gpg -er AskApache >`date +%m%d%y-%H%M.$_N.sqls`
2009-08-18 07:03:08
User: AskApache
Functions: eval gpg sed

The coolest way I've found to backup a wordpress mysql database using encryption, and using local variables created directly from the wp-config.php file so that you don't have to type them- which would allow someone sniffing your terminal or viewing your shell history to see your info.

I use a variation of this for my servers that have hundreds of wordpress installs and databases by using a find command for the wp-config.php file and passing that through xargs to my function.

VARNAMES='ID FORENAME LASTNAME ADDRESS CITY PHONE MOBILE MAIL' ; cat customer.csv | while read LINE ; do COUNT=1 ; for VAR in $VARNAMES ; do eval "${VAR}=`echo $LINE | /usr/bin/awk {'print $'$COUNT''}`" ; let COUNT=COUNT+1 ; done ; done
2009-05-19 11:23:00
User: GeckoDH
Functions: cat eval read


cat customer.csv | while read LINE ; do


for VAR in $VARNAMES ; do

eval "${VAR}=`echo $LINE | /usr/bin/awk {'print $'$COUNT''}`"




Maybe you have a CSV-File with addresses, where you have to process each contact (one per line, write each value to own variable). Of course you can define every variable, but this way is more simple and faster (to write).

VARNAMES includes the variable names. Pay attention: the number of names in VARNAMES have to be the same than in the CSV-file the fields. If the CSV is not seperated with ";", you can set the seperator after the awk-binary with -F"_" for example.

expanded_script=$(eval "echo \"$(cat ${sed_script_file})\"") && sed -e "${expanded_script}" your_input_file
2009-05-07 14:21:14
Functions: eval sed

With this command you can use shell variables inside sed scripts.

This is useful if the script MUST remain in an external file, otherwise you can simply use an inline -e argument to sed.

mkdir() { /bin/mkdir $@ && eval cd "\$$#"; }
eval "`dircolors -b`"
2009-03-27 05:37:04
User: isaacs
Functions: eval
Tags: ls

If you put this in your .bashrc, you might also want to add this to make it use the colors by default:

alias ls="ls --color=auto"