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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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escape any command aliases

e.g. if rm is aliased for 'rm -i', you can escape the alias by prepending a backslash: rm [file] # WILL prompt for confirmation per the alias \rm [file] # will NOT prompt for confirmation per the default behavior of the command

Concatenates lines using sed

Files extension change

Changing a file extension to a new one for all files in a directory.

Recursively list all of the files in a directory, group them by extension and calculate the average of the file sizes in each group

Here's an annotated version of the command, using full-names instead of aliases. It is exactly equivalent to the short-hand version. # Recursively list all the files in the current directory. Get-ChildItem -Recurse | # Filter out the sub-directories themselves. Where-Object { return -not $_.PsIsContainer; } | # Group the resulting files by their extensions. Group-Object Extension | # Pluck the Name and Count properties of each group and define # a custom expression that calculates the average of the sizes # of the files in that group. # The back-tick is a line-continuation character. Select-Object ` Name, Count, @{ Name = 'Average'; Expression = { # Average the Length (sizes) of the files in the current group. return ($_.Group | Measure-Object -Average Length).Average; } } | # Format the results in a tabular view, automatically adjusted to # widths of the values in the columns. Format-Table -AutoSize ` @{ # Rename the Name property to something more sensible. Name = 'Extension'; Expression = { return $_.Name; } }, Count, @{ # Format the Average property to display KB instead of bytes # and use a formatting string to show it rounded to two decimals. Name = 'Average Size (KB)'; # The "1KB" is a built-in constant which is equal to 1024. Expression = { return $_.Average / 1KB }; FormatString = '{0:N2}' }

How to run X without any graphics hardware

This starts an X server using Xvfb(1) (no graphics hardware required), then starts a VNC server on the display. Change :1 if there's a conflict with an existing display, and change 800x600x24 to suit your tastes (24 is the bit depth, 800x600 is the size). This command obviously requires X be installed, and also x11vnc(1); both are available via your favourite package manager. You can also use another VNC server of your choosing, as long as DISPLAY is set to the display of Xvfb(1). To change your desktop environment (the default is twm(1), which is rather fail), you can add it to your ~/.xinitrc file (see the startx(1) manpage for details).

Start a quick rsync daemon for fast copying on internal secure network

"Sample output" shows a minimalistic configuration file.

Retrieve the size of a file on a server

- Where $URL is the URL of the file. - Replace the $2 by $3 at the end to get a human-readable size. Credits to svanberg @ ArchLinux forums for original idea. Edit: Replaced command with better version by FRUiT. (removed unnecessary grep)

Find unused IPs on a given subnet

Somewhat shorter version.

take execution time of several commands

The last ; is important. example: time { rm -rf /folder/bar && mkdir -p /folder/bar ; echo "done" ; } command is a bash builtin

Which processes are listening on a specific port (e.g. port 80)

swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

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Commands using echo (1,545)

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