Commands tagged expansion sorted by votes

Commands tagged expansion (7)

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prevent accidents while using wildcards

alternative for "echo rm *.txt". Just doubletab the command you are willing to use and it will show you the affected files. Show Sample Output
This is sample output - yours may be different.
```
linux:/tmp # rm *.txt
wildcard.txt   tab.txt
```
25

rm *.txt <TAB> <TAB>

boschi · 2010-11-04 13:58:15 12
prevent accidents and test your command with echo

if you're using wildcards * or ? in your command, and if you're deleting, moving multiple files, it's always safe to see how those wildcards will expand. if you put "echo" in front of your command, the expanded form of your command will be printed. It's better safe than sorry. Show Sample Output
This is sample output - yours may be different.
```
rm 1.txt 2.txt 3.txt 4.txt
```
11

echo rm *.txt

alperyilmaz · 2010-10-27 07:26:26 7
Isolate file name from full path/find output

Quick method of isolating filenames from a full path using expansion. Much quicker than using "basename" Show Sample Output
This is sample output - yours may be different.
```
where fullpath="./path/to/filename.txt"
echo ${fullpath##*/} returns "filename.txt"
```
9

echo ${fullpath##*/}

quincymd · 2010-07-21 22:35:29 11

Use a var with more text only if it exists

See "Parameter Expansion" in the bash manpage. They refer to this as "Use Alternate Value", but we're including the var in the at alternative. Show Sample Output

command ${MYVAR:+--someoption=$MYVAR}

pdxdoughnut · 2015-11-04 19:47:24 11

expand a program-name into an absolute path on the bash command-line, using ctrl-e

Tested with bash v4.1.5 on ubuntu 10.10 Limitations: as written above, only works for programs with no file extention (i.e 'proggy', but not 'proggy.sh') because \eb maps to readine function backward-word rather then shell-backward-word (which is unbinded by default on ubuntu), and correspondingly for \ef. if you're willing to have Ctrl-f and Ctrl-g taken up too , you can insert the following lines into ~/.inputrc, in which case invoking Ctrl-e will do the right thing both for "proggy" and "proggy.sh". -- cut here -- \C-f:shell-backward-word \C-g:shell-forward-word "\C-e":"\C-f`which \C-g`\e\C-e" -- cut here -- Show Sample Output
This is sample output - yours may be different.
```
Bash$ sudo myscript<Ctrl+e>

becomes:

Bash$ sudo /home/user/bin/myscript
```
0

bind '"\C-e":"\eb `which \ef`\e\C-e"'

jennings6k · 2011-01-26 16:11:52 10
Run an interactive program with perl code expansion

Start an interactive program with perl code expansion. Everything between #[ ] is evaluated as perl code. #[ ] tags must not be nested (it wouldn't make sense anyway). Show Sample Output
This is sample output - yours may be different.
```
plexpand sed -s 's/a/x/g'
banana
bxnxnx
b#["an"x2]a
bxnxnx
```
0

plexpand() { mkfifo /tmp/plxpnd; $@ </tmp/plxpnd & perl -p -e '$|=1; s/#\[(.*)\]/eval($1)/ge' >/tmp/plxpnd; rm /tmp/plxpnd; }

hellcode · 2016-05-10 04:49:35 9
MS-DOS only: Enable variable expansion from inside of FOR loops with !varname!

Usually the MS-DOS cmd.exe processes in the whole FOR loop as one command and expands each var like %varname% in before (except the loop var of course). This command enables expansion of other vars than only the loop var during the FOR loop. The syntax of the var to expand is then !varname! inside the FOR loop. Use command endlocal to end the setlocal command. E.g. (only works from batch files, not from commandline directly): @echo off setlocal enabledelayedexpansion FOR %%A IN (*) DO ( set file=%%A echo !file! ) endlocal
This is sample output - yours may be different.
-1

setlocal enabledelayedexpansion

Marco · 2010-08-10 12:26:43 7

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Remind yourself every 15 minutes (repeated reminders)

Note: 1) -n option of watch accepts seconds 2) -t option of notify-send accepts milliseconds 3) All quotes stated in the given example are required if notification message is more than a word. 4) I couldn't get this to run in background (use of & at the end fails). Any suggestions/improvements welcome.

find out how much space are occuipied by files smaller than 1024K

The command gives size of all files smaller than 1024k, this information, together with disk usage, can help determin file system parameter (e.g. block size) or storage device (e.g. SSD v.s. HDD). Note if you use awk instead of "cut| dc", you easily breach maximum allowed number of records in awk.

Copy with progress

Create a temporary file

To create directory, use: $ tempdir=$(/bin/mktemp -d)

Unrar multiple directories into current working directory

Grabs all rar files in any current subdirectories and feeds it to unrar. Doesn't work well with things packaged like file.part01.rar. Works best with File.rar. You can recurse into other directories by adding more /*'s

shorten url using curl, sed and is.gd

Just create a function in your .bashrc like this shorturl() { curl -s -d URL="$1" http://is.gd/create.php | sed '/Your new shortened/!d;s/.*value="$[^"]*$".*/\1/' }

Find usb device in realtime

Using this command you can track a moment when usb device was attached.

Connect-back shell using Bash built-ins

Connect-back shell using Bash built-ins. Useful in a web app penetration test, if it's the case of a locked down environment, without the need for file uploads or a writable directory. -- /dev/tcp and /dev/udb redirects must be enabled at compile time in Bash. Most Linux distros enable this feature by default but at least Debian is known to disable it. -- http://labs.neohapsis.com/2008/04/17/connect-back-shell-literally/

Which .service related this file?

I use this as an alias to get all .service files related a single installed file/conf (if it has services, of course). For rpm based systems ;)

Duplicating service runlevel configurations from one server to another.

And then to complete the task: Go to target host; $ssh host Turn everything off: $for i in `chkconfig --list | fgrep :on | awk '{print $1}'` ; do chkconfig --level 12345 $i off; done Create duplicate config: $while read line; do chkconfig --level $line on; done < foo

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Commands tagged expansion (7)

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