Login or Register to Ask a Question and Join Our Community

Sponsored Content
Full Discussion: Bash Parameter Expansion
Top Forums Shell Programming and Scripting Bash Parameter Expansion Post 303013629 by bakunin on Saturday 24th of February 2018 03:12:30 PM
Old 02-24-2018
Quote:
Originally Posted by kristinu
Is there a way to get the filename without the directory and without the extension, using parameter expansion to get

Code:
  iv.hpac..hhz.d.2016.250.070018

Yes, but it would be cumbersome and plain ugly. Writing scripts (i suppose you need it in a script) is all about clarity and making it easy to understand what is done, therefore you should do it in two steps using the expansions you already found. I would write it like this:

Code:
text="${text##*/}"      # cut off the path
text="${text%.*}"       # cut off the extension

For completeness' (but again: don't really do it! This is just to show off my prowess in writing incomprehensible code! ;-) ) sake: you can use an expansion inside another expansion as a pattern. For instance, this cuts off the first character in a string, notice the nested expansion:

Code:
chLine="abcdefghi"

while [ -n "$chLine" ] ; do
     chChar="${chLine%${chLine#?}}"        # nested expansion!!
     chLine="${chLine#?}"

     echo char is: \"$chChar\"
     echo line is: \"$chLine\"
done

Using this device you could do what you want. Don't!

I hope this helps.

bakunin
These 2 Users Gave Thanks to bakunin For This Post:
apmcd47 kristinu
 

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

removing html tags via parameter expansion

Hi all- I have a variable that contains a web page: echo $STUFF <html> <head> <title>my page</title></head> <body> blah blah etc.. Can I use the shell's parameter expansion abilities to remove just the tags? I thought that FIXHTML=${STUFF//<*>/} might do it, but it didn't seem to... (2 Replies)
Discussion started by: rev66
2 Replies

2. Shell Programming and Scripting

Need help with parameter expansion

Say you have this numeric variable that can be set by the user but you never want it to leave a certain range when it gets printed. How could you use parameter expansion such that it will never expand outside of that boundary? Thanks ---------- Post updated at 11:09 PM ---------- Previous update... (3 Replies)
Discussion started by: stevenswj
3 Replies

3. Shell Programming and Scripting

Bash parameter expansion from a config file

Hi - I am trying to do a simple config file with known variable names in it, e.g.: contents of config file a.conf: -a -b $work -c $host simplified contents of bash script file: work='trunk' host='alaska' opts=$(tr '\n' ' ' < a.conf) opts="$opts $*" mycommand $opts arg1 arg2 The... (3 Replies)
Discussion started by: mrengert
3 Replies

4. Shell Programming and Scripting

Parameter expansion not working for all strings...

I'm trying to write a script that parses my music collection and hard link some filenames that my media player doesn't like to other names. To do this I need to extract the name and remove alla non ASCII characters from that and do a cp -l with the result. Problem is this: 22:16:58 $... (8 Replies)
Discussion started by: refuser
8 Replies

5. UNIX for Dummies Questions & Answers

Parameter Expansion with regular expression

Hello experts, I am exploring parameter expansion, and trying to cut the fields in a URL. Following is the requirement: I have // abc.nnt /dir1/dir2/dir3/dir4/somefile.java What i need to get is the path after dir3, and dir3 will be passed. output that i need is... (1 Reply)
Discussion started by: gjarms
1 Replies

6. Shell Programming and Scripting

Bash expansion

Hello. I cannot write a command without using eval. Any help is welcome Note 1 : What does the function SOMETHING has no importance. Note 2 : What does the command find has no importance. It is an expansion variable problem : where to put or or or anythings else What works (FILTRE_1... (8 Replies)
Discussion started by: jcdole
8 Replies

7. Shell Programming and Scripting

Bash Parameter Expansion

#!/bin/bash SNMPW='/usr/bin/snmpwalk' while read h i do loc=$($SNMPW -v3 -u 'Myusername' -l authPriv -a SHA -A 'Password1' -x AES -X 'Password2' $i sysLocation.0 2>/dev/null) loc=${loc:-" is not snmpable."} loc=${loc##*: } loc=${loc//,/} echo "$i,$h,$loc" done < $1 My question is ... ... (1 Reply)
Discussion started by: sumguy
1 Replies

8. Shell Programming and Scripting

Bash : More parameter expansion and IFS

I am trying to become more fluent with the interworking of bash and minimize the number of external calls. Sample Data. This will be the response of the snmp query. SNMPv2-MIB::sysName.0 = STRING: SomeHostName SNMPv2-MIB::sysObjectID.0 = OID: SNMPv2-SMI::enterprises.9.1.1745... (5 Replies)
Discussion started by: sumguy
5 Replies

9. Shell Programming and Scripting

Bash : Parameter expansion ${var:-file*}

Example data $ ls *somehost* 10.10.10.10_somehost1.xyz.com.log 11.11.11.11_somehost2.xyz.com.log #!/bin/bash #FILES="*.log" FILES=${FILES:-*.log} for x in $FILES do ip="${x%%_*}" # isolate IP address x="${x##*_}" # isolate hostname hnam="${x%.*}" # Remove the ".log"... (2 Replies)
Discussion started by: popeye
2 Replies

10. Shell Programming and Scripting

Use parameter expansion over a parameter expansion in bash.

Hello All, Could you please do help me here as I would like to perform parameter expansion in shell over a parameter expansion. Let's say I have following variable. path="/var/talend/nat/cdc" Now to get only nat I could do following. path1="${path%/*}" path1="${path1##*/}" Here... (8 Replies)
Discussion started by: RavinderSingh13
8 Replies

LEARN ABOUT CENTOS

kpsewhich

KPSEWHICH(1)						      General Commands Manual						      KPSEWHICH(1)

NAME

       kpsewhich - standalone path lookup and and expansion for kpathsea

SYNOPSIS

       kpsewhich [options] [filenames]

DESCRIPTION

       This manual page is not meant to be exhaustive.	The complete documentation for this version of TeX can be found in the info file or manual
       Kpathsea: A library for path searching.

       kpsewhich is used as a standalone front-end of the kpathsea library that can be used to examine variables and find files.  When the -format
       option is not given, the search path used when looking for a file is inferred from the name given, by looking for a known extension.  If no
       known extension is found, the search path for TeX source files is used.

OPTIONS

       kpsewhich accepts the following options:

       -debug num
	      Set debugging flags.

       -D num Use a base resolution of num; the default, set by the installer, is typically 600.

       -dpi num
	      As -D.

       -engine string
	      Set $engine in the environment, which is used in some search paths.

       -expand-braces string
	      Print variable and brace expansion of string.

       -expand-path string
	      Print complete path expansion of string.

       -expand-var string
	      Print variable expansion of string.

       -format name
	      Use file type name.  See the info manual for a list of valid names, or use the -help option to print the list.

       -help  Print help message and exit.

       -interactive
	      Ask for additional filenames to look up.

       -mktex fmt
	      enable mktexfmt generation.  (fmt=pk/mf/tex/tfm)

       -mode string
	      Set device name for $MAKETEX_MODE to string; no default.

       -must-exist
	      Search the disk as well as ls-R if necessary.

       -no-mktex fmt
	      disable mktexfmt generation.  (fmt=pk/mf/tex/tfm)

       -path string
	      Search in the path string.

       -progname string
	      Set program name to string.

       -show-path name
	      Output search path for file type name.  See the info manual for a list of valid names, or use the -help option to print the list.

       -var-value variable
	      Print the expansion of variable.

       -version
	      Print version information and exit.

SEE ALSO

       mktexlsr(1), mktexmf(1), mktexpk(1), mktextfm(1).

Kpathsea 6.1.0							   1 March 2011 						      KPSEWHICH(1)
All times are GMT -4. The time now is 02:55 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy