Commands using echo sorted by votes

Commands using echo (1,545)

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cd to (or operate on) a file across parallel directories

ksh's version of cd has an optional syntax where you can type "cd old new" and it will replace "old" with "new" in your current directory and take you there. This is very handy when you have a parallel directory structure, like source and object directories. As suggested, you can just type cd ${PWD/old/new} to get this in bash, but this function in your .bashrc will let you type the ksh cd syntax and avoid typing the special characters while preserving other cd functionality. Show Sample Output
This is sample output - yours may be different.
```
splante@guinness:/tmp/src/x/y/z/> cd src obj
splante@guinness:/tmp/obj/x/y/z/> cd obj src
splante@guinness:/tmp/src/x/y/z/> 
```
0

cd () { cdop=""; while [ "$1" != "${1#-}" ]; do cdop="${cdop} ${1}"; shift; done; if [ $# -eq 2 ]; then newdir="${PWD/$1/$2}"; [ -d "${newdir}" ] || { echo "no ${newdir}"; return 1; }; builtin cd $cdop "${newdir}"; else builtin cd $cdop "$@"; fi }

splante · 2011-04-07 14:36:26 3
List your MACs address
This is sample output - yours may be different.
0

echo | ifconfig | grep HWaddr

malto · 2011-04-12 23:59:54 3
resolve hostname to IP our vice versa with less output

The host command comes with the bind-utils package, which is has a better chance to be installed than resolveip from mysql. The last word of the query result is displayed, which is the last result host got. This works with CNAMEs. You get "3(NXDOMAIN)" in case of failure. Show Sample Output
This is sample output - yours may be different.
```
192.0.32.10
```
0

hostresult=$(host -t A www.example.com); echo "${hostresult##* }"

kilx · 2011-04-21 10:16:50 4
un-escape URL/URIs with Ruby
This is sample output - yours may be different.
0

echo 'example.com%2Fsome%2Fpath' | ruby -r'cgi' -e 'puts CGI.unescape(STDIN.read)'

slippyd · 2011-04-26 03:13:22 3
replace one of the octates of an IP

the numbers in the ip address are represented in sed as \1\2\3\4. If I put \1\2\3$i, then I change the last number. So for example to change the second number I'll do \1$i\3\4. Regards, Kfir Show Sample Output
This is sample output - yours may be different.
```
10.0.0.3
```
0

i=3; echo 10.0.0.1 | sed "s/$[0-9]\{1,3\}\.$$[0-9]\{1,3\}\.$$[0-9]\{1,3\}\.$$[0-9]\{1,3\}$/\1\2\3$i/g"

kipibenkipod · 2011-04-27 14:08:02 3
print line and execute it in BASH

since we're repeating the command there after the semicolon, we only need one backtick Show Sample Output
This is sample output - yours may be different.
```
$ echo "ls"; `!#:0-$

echo "ls"; `echo "ls" ; `
ls
Android.mk  ardrv  devmgr  egl  file1
```
0

$ echo "command"; `!#:0-$

unixmonkey20949 · 2011-04-28 17:09:25 3
Persistent saving of iptables rules

Should run with sudo
This is sample output - yours may be different.
0

cd /etc/network/if-up.d && iptables-save > firewall.conf && echo -e '#!/bin/sh -e\niptables-restore < $(dirname $0)/firewall.conf' > iptables && chmod a+x iptables

pkufranky · 2011-05-01 03:23:26 3
Create cheap and easy index.html file

Just to avoid link to itself
This is sample output - yours may be different.
0

F=index.html; for i in *; do [[ $i = $F ]] && continue; echo "<li><a href='$i'>$i</a>"; done >$F

frans · 2011-05-08 20:57:24 5
Display GCC Predefined Macros

another one
This is sample output - yours may be different.
0

echo | gcc -dM -E -

Byung · 2011-05-09 09:59:24 3
Show seconds since modified of newest modified file in directory
This is sample output - yours may be different.
0

FILE=`ls -ltr /var/lib/pgsql/backups/daily/ | tail -n1 | awk '{print $NF}'`; TIME=`stat -c %Y /var/lib/pgsql/backups/daily/$FILE`; NOW=`date +%s`; echo $((NOW-TIME))

allrightname · 2011-05-12 13:21:37 6
log rm commands

Sometimes, it is annoying to find your files or directories missing. If you want to log all the rm commands you can put this in /etc/profile.
This is sample output - yours may be different.
0

function rm { workingdir=$( pwdx $$ | awk '{print $2}' ) /usr/bin/rm $* echo "rm $* issued at $(date) by the user $(who am i| awk '{print $1} ') in the directory ${workingdir}" >> /tmp/rm.out }

soulonfire · 2011-06-22 14:47:38 21
Create a temp file

Another way to create temp files in your scripts, if tempfile fails, it will create a hidden local file in the current directory, don't forget to delete $FILE
This is sample output - yours may be different.
0

FILE=$(tempfile 2>/dev/null || echo .$RANDOM)

h3nr1x · 2011-06-22 15:12:21 3
Check if commands are available on your system
This is sample output - yours may be different.
0

for c in gcc bison dialog bc asdf; do if ! which $c >/dev/null; then echo Required program $c is missing ; exit 1; fi; done

Mozai · 2011-06-27 12:54:02 3
Discover unoptimized MySQL tables and optimize them.

Finds all tables that need optimising and loops through them, running optimise against them. This works server-wide, on all databases and tables.
This is sample output - yours may be different.
0

for table in $(echo "select concat(TABLE_SCHEMA, '.', TABLE_NAME) from information_schema.TABLES where TABLE_SCHEMA NOT IN ('information_schema','mysql') and Data_free > 0" | mysql --skip-column-names); do echo "optimize table ${table}" | mysql; done;

Xiol · 2011-06-28 21:09:57 4
print an 'hello world'
This is sample output - yours may be different.
0

echo 'hello world'

aykut · 2011-07-06 17:54:47 3
Find .java files with high complexity (counting curly braces)
This is sample output - yours may be different.
0

find src/ -name "*.java" | while read f; do echo -n "$f "; cat "$f" | tr -dc '{}'; echo; done | awk '{ print length($2), $1 }' | sort -n

mindsocket · 2011-07-21 01:25:31 8
split a string (2)
This is sample output - yours may be different.
0

read VAR1 VAR2 VAR3 <<< aa bb cc; echo $VAR2

h3xx · 2011-07-24 18:56:30 3
Create a QR code image in MECARD format

If your contact information was entered when your user account was created (it gets added to /etc/passwd) then this gets that info and creates a QR code for you automatically
This is sample output - yours may be different.
0

getent passwd $(whoami) | echo "$(perl -ne '/^([^:]+):[^:]+:[^:]+:[^:]+:([^ ]+) ?([^,]+)?,([^,]*),([^,]*),([^:,]*),?([^:,]*)/ and printf "MECARD:N:$3,$2;ADR:$5;TEL:$4;TEL:$6;EMAIL:$1@"')$HOSTNAME;;" | qrencode -o myqr.png

Strawp · 2011-07-25 12:59:57 3
progress bar for cp

Cleaner, but probably less portable. Works with bash4 and should also work on bash3. IIRC, $(()) and (()) are bashisms, not POSIX. Show Sample Output
This is sample output - yours may be different.
```
[========================================================>.............] 81%
```
0

while [$((or_sz=$(stat -c %s "$1"))) -gt $((ds_sz=$(stat -c %s "$2")))];do ((pct=(69*$ds_sz)/$or_sz));echo -en "\r[";for ((i=1;i<=pct;i++));do echo -n "=";done;echo -n \>;for ((i=pct;i<=68;i++));do echo -n ".";done;echo -n "] $(((100*$pct)/69))%";done

ScriptFanix · 2011-07-29 17:41:56 3
See how many more processes are allowed, awesome!
This is sample output - yours may be different.
0

echo $(($(ulimit -u)-$(pgrep -u $USER|wc -l))

h3xx · 2011-07-30 05:03:36 3
Grep across a directory and open matching files in vim (one tab per file)

vim 7 required
This is sample output - yours may be different.
0

vim -p `grep -r PATTERN TARGET_DIR | cut -f1 -d: | sort | uniq | xargs echo -n`

kovagoz · 2011-08-05 16:34:31 4
Check if your webserver supports gzip compression with curl
This is sample output - yours may be different.
0

if curl -s -I -H "Accept-Encoding: gzip,deflate" http://example.com/ | grep 'Content-Encoding: gzip' >/dev/null 2>&1 ; then echo Yes; else echo No;fi

rwky · 2011-08-16 21:48:14 3
Sum size of files returned from FIND

Just an alternative. Here the output of the subshell statement is a complete script for dc so you can save it, manipulate it with some other tool or just debug it with less.
This is sample output - yours may be different.
0

(echo 0; find [args...] -printf '%s +\n'; echo p) | dc

wipu · 2011-08-17 07:49:55 4
Print repeating CSV values on new lines - normalize repeating fields

Lets say you have a file with the following layout: LINUX,DIR,FILE1,FILE2,FILE3 You want the file to look like this: LINUX,DIR,FILE1 LINUX,DIR,FILE2 LINUX,DIR,FILE3 This perl command does it for you. Show Sample Output
This is sample output - yours may be different.
```
LINUX,DIR,FILE1
LINUX,DIR,FILE2
LINUX,DIR,FILE3
```
0

echo "LINUX,DIR,FILE1,FILE2,FILE3" | perl -aF, -nle 'my ($fld1, $fld2, @fields) = @F; while(@fields) { print join ",", $fld1, $fld2, splice(@fields, 0, 1) }'

mindrape · 2011-08-22 18:27:12 4
Pipe stdout to image and mail

sudo /sbin/ifconfig | gotxt2imgmail you@example.com
This is sample output - yours may be different.
0

gotxt2imgmail() { if [ $# != 1 ]; then echo 'gotxt2imgmail < email >'; return; fi; e="$1"; f=$RANDOM.png; convert label:@- $f; echo "" | mailx -s $f -a $f $e }

meathive · 2011-08-24 12:05:05 3
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Ultimate current directory usage command

A little bit smaller, faster and should handle files with special characters in the name.

Find top 5 big files

zsh: list of files sorted by size, greater than 100mb, head the top 5. '**/*' is recursive, and the glob qualifiers provide '.' = regular file, 'L' size, which is followed by 'm' = 'megabyte', and finally '+100' = a value of 100

Remove all subversion files from a project recursively

This command will remove all .svn folder from your project if you need to manual remove the subversion files.

Batch Convert SVG to PNG (in parallel)

Convert some SVG files into PNG using ImageMagick's convert command. Run the conversions in parallel to save time. This is safer than robinro's forkbomb approach :-) xargs runs four processes at a time -P4

m4a to mp3 conversion with ffmpeg and lame

A batch file version of the same command would be: for f in *.m4a; do ffmpeg -i "$f" -acodec libmp3lame -ab 256k "${f%.m4a}.mp3"; done

Mount directories in different locations

Like symlinked directories, you can mount a directory at a different location. For example mounting a directory from one location in to the http root without having to make your program follow symlinks or change permissions when reading.

Printable random characters

Reads psuedorandom bytes from /dev/urandom, filtering out non-printable ones. Other character classes can be used, such as [:alpha:], [:digit:] and [:alnum:]. To get a string of 10 lowercase letters: $ tr -dc '[:lower:]' < /dev/urandom | head -c 10

Download a file and uncompress it while it downloads

This will uncompress the file while it's being downloaded which makes it much faster

list files recursively by size

generate random mac address

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Commands using echo (1,545)

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