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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
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Commands by flatcap from sorted by
Terminal - Commands by flatcap - 47 results
for i in /var/spool/cron/*; do echo ${i##*/}; sed 's/^/\t/' $i; echo; done
cal 04 2012 | awk '{ $7 && X=$7 } END { print X }'
2012-05-06 23:43:21
User: flatcap
Functions: awk cal

If your locale has Monday as the first day of the week, like mine in the UK, change the two $7 into $6

find . ! -regex '.*/\(unit-test\|android\)/.*' \( -name '*.c' -o -name '*.cpp' \)
2012-04-26 17:53:45
User: flatcap
Functions: find
Tags: find

Find files matching multiple descriptions (*.c and *.cpp) excluding multiple directories (unit-test and android).

find . -type f -print0 | xargs -0 du -h | sort -hr | head -20
2012-03-30 10:21:12
User: flatcap
Functions: du find head sort xargs

Search for files and list the 20 largest.

find . -type f

gives us a list of file, recursively, starting from here (.)

-print0 | xargs -0 du -h

separate the names of files with NULL characters, so we're not confused by spaces

then xargs run the du command to find their size (in human-readable form -- 64M not 64123456)

| sort -hr

use sort to arrange the list in size order. sort -h knows that 1M is bigger than 9K

| head -20

finally only select the top twenty out of the list

for w in $(tr 'A-Z ,."()?!;:' 'a-z\n' < sample.txt); do echo ${#w} $w; done | sort -u | sort -n
2012-03-15 14:14:11
User: flatcap
Functions: echo sort tr
Tags: bash sort tr

Take a file and ,."()?!;: give a list of all the words in order of increasing length.

First of all use tr to map all alphabetic characters to lower case and also strip out any puntuation.

A-Z become a-z

,."()?!;: all become \n (newline)

I've ignored - (hyphen) and ' (apostrophe) because they occur in words.

Next use bash to print the length ${#w} and the word

Finally sort the list numerically (sort -n) and remove any duplicates (sort -u).

Note: sort -nu performs strangely on this list. It outputs one word per length.

for i in *; do sed -i "s/^/$i: /" $i; done
mysql -u root -p -BNe "select host,count(host) from processlist group by host;" information_schema
2011-12-22 10:35:23
User: flatcap
Tags: mysql

Count the number of active connections to a MySQL database.

The MySQL command "show processlist" gives a list of all the active clients.

However, by using the processlist table, in the information_schema database, we can sort and count the results within MySQL.

printf "$PWD/%s\n" *
2011-12-16 13:43:01
User: flatcap
Functions: printf
Tags: printf

List the full path of some files.

You can add ".*" on the end if you want to display hidden files.

sed -n '3,6p' /path/to/file
2011-12-14 15:09:38
User: flatcap
Functions: sed
Tags: sed

Print all lines between two line numbers

This command uses sed(1) to print all lines between two known line numbers in a file. Useful for seeing output in a log file, where the line numbers are known. The above command will print all lines between, and including, lines 3 and 6.

UUID="63b726a0-4c59-45e4-af65-bced5d268456"; echo ${UUID//-/}
2011-11-22 22:49:30
User: flatcap
Functions: echo

Remove the dashes from a UUID using bash search and replace.

whichpkg() { rpm -qf "[email protected]"; }
2011-07-05 23:39:32
User: flatcap
Functions: rpm
Tags: rpm

Find the package a file belongs to on an rpm-based distro.

summpkg() { rpm -qfi "[email protected]"; }
2011-07-05 23:39:24
User: flatcap
Functions: rpm
Tags: rpm

Find information about the rpm package which owns a certain file.

find . -type f -newermt "2010-01-01" ! -newermt "2010-06-01"
2011-06-26 09:52:26
User: flatcap
Functions: find
Tags: find dates

Find files in a specific date range - in this case, the first half of last year.

-newermt = modification time of the file is more recent than this date

GNU find allows any date specfication that GNU date would accept, e.g.

find . -type f -newermt "3 years ago" ! -newermt "2 years ago"


find . -type f -newermt "last monday"
cd() { if [ -n "$1" ]; then [ -f "$1" ] && set -- "${1%/*}"; else [ -n "$CDDIR" ] && set -- "$CDDIR"; fi; command cd "[email protected]"; }
2011-06-24 08:48:13
User: flatcap
Functions: cd command set
Tags: cd test set

Move efficiently between directories.


This command adds a couple of extra features to cd, without affecting normal use.

CDPATH use is also unaffected. It introduces and environment variable CDDIR which is used as an alternate home directory.


Note: I don't want to alter $HOME because then all my dot files will move.




cd dir

Change directory to "dir" (using CDPATH if necessary)


cd dir/file.txt

Change directory to "dir" (containing folder of "file.txt")

This allows you to cut'n'paste, or use


CDDIR is unset


Change directory to $HOME




Change directory to /home/flatcap/work


For convenience, put the command, and the following, in your .bashrc or .bash_profile

export CDDIR="/home/flatcap/work"

alias cdd="CDDIR=$(pwd)"

rf() { for i in "[email protected]"; do mv "$i" "$(pwgen 8 1).${i##*.}"; done }
2011-06-22 07:45:23
User: flatcap
Functions: mv

Give files a random name (don't ask why :-)

The function will rename files but maintain their extensions.

BUG: If a file doesn't have an extension it will end up with a dot at the end of the name.

The parameter '8' for pwgen controls the length of filenames - eight random characters.

find . -type f -name \*.php | while IFS="" read i; do expand -t4 "$i" > "$i-"; mv "$i-" "$i"; done
2011-04-08 12:53:14
User: flatcap
Functions: expand find mv read

Recursively find php files and replace tab characters with spaces.


"\*.php" -- replace this with the files you wish to find

"expand" -- replace tabs with spaces (use "unexpand" to replace spaces with tabs)

"-t4" -- tabs represent 4 spaces

Note: The IFS="" in the middle is to prevent 'read' from eating leading/trailing whitespace in filenames.

ls -1 | sort -R | sed -n 's/^/Selected /;1p'
MIN=10;for ((i=MIN*60;i>=0;i--));do echo -ne "\r$(date -d"0+$i sec" +%H:%M:%S)";sleep 1;done
2011-02-20 11:56:28
User: flatcap
Functions: echo sleep

Countdown clock - Counts down from $MIN minutes to zero.

I let the date command do the maths.

This version doesn't use seq.

s(){ sed 's/./\n\0/g'<<<$1|sort;};cmp -s <(s foobar) <(s farboo)||echo -n "not ";echo anagram
2011-02-17 12:42:45
User: flatcap
Functions: cmp echo sed

Are the two strings anagrams of one another?

sed splits up the strings into one character per line

the result is sorted

cmp compares the results

Note: This is not pretty. I just wanted to see if I could do it in bash.

Note: It uses fewer characters than the perl version :-)

files -type f | xargs -n100 | while read l; do mkdir $((++f)); cp $l $f; done
2011-02-15 23:15:16
User: flatcap
Functions: cp mkdir read xargs

Take a folder full of files and split it into smaller folders containing a maximum number of files. In this case, 100 files per directory.

find creates the list of files

xargs breaks up the list into groups of 100

for each group, create a directory and copy in the files

Note: This command won't work if there is whitespace in the filenames (but then again, neither do the alternative commands :-)

for((r=1;r<10;r++));do v=1;echo -n "$v ";for((c=1;c<$r;c++));do v2=$(($(echo "$v*($r-$c)/$c")));echo -n "$v2 ";v=$v2;done;echo;done
2011-02-10 18:38:04
User: flatcap
Functions: echo
Tags: bash math


This one's for bartonski. Enjoy.

132 characters. I'm sure we can do better.

Note: after row 64 we overflow integer maths.

seq 1 2 99999999 | sed 's!^!4/!' | paste -sd-+ | bc -l
2011-02-09 23:36:07
User: flatcap
Functions: bc paste sed seq
Tags: sed seq bc paste math

Calculate pi from the infinite series 4/1 - 4/3 + 4/5 - 4/7 + ...

This expansion was formulated by Gottfried Leibniz: http://en.wikipedia.org/wiki/Leibniz_formula_for_pi

I helped rubenmoran create the sum of a sequence of numbers and he replied with a command for the sequence: 1 + 2 -3 + 4 ...

This set me thinking. Transcendental numbers!

seq provides the odd numbers 1, 3, 5

sed turns them into 4/1 4/3 4/5

paste inserts - and +

bc -l does the calculation

Note: 100 million iterations takes quite a while. 1 billion and I run out of memory.