Sponsored Content
Top Forums Shell Programming and Scripting Need bash script to use a sed command as a variable Post 303038034 by Scrutinizer on Thursday 22nd of August 2019 03:25:16 AM
Old 08-22-2019
Yes that was indeed not a good approach. Also a good thing you pointed out that the shell approach only gives a proper answer if inet is present in the file. But this would still not solve that issue.

This may be more appropriate:

Code:
while read key value; do
  if [ "$key" = inet ]; then
    ip=$value
  fi
done < config.boot


Last edited by Scrutinizer; 08-22-2019 at 04:39 AM..
 

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

BASH -- sed -- variable

Hi, I'm new at bash scripting -- can anyone here help me about the sed command? I need to be able to edit and or delete a text from an outside file ie file.txt -- I'm passing a variable and not a string I was thinking of something like echo -n "What do you want to edit?: " read edit sed... (1 Reply)
Discussion started by: Imajean
1 Replies

2. Shell Programming and Scripting

passing variable from bash to perl from bash script

Hi All, I need to pass a variable to perl script from bash script, where in perl i am using if condition. Here is the cmd what i am using in perl FROM_DATE="06/05/2008" TO_DATE="07/05/2008" "perl -ne ' print if ( $_ >="$FROM_DATE" && $_ <= "$TO_DATE" ) ' filename" filename has... (10 Replies)
Discussion started by: arsidh
10 Replies

3. Shell Programming and Scripting

Special characters in a bash variable in sed

Hello, I am trying the following: echo __CHANGEME__ >> testfile VAR1="&&&" sed -i "s|__CHANGEME__|${VAR1}|" testfile cat testfile This results in testfile containing __CHANGEME____CHANGEME____CHANGEME__ Whereas I want it to result in &&& I understand that if VAR1="\&\&\&" then... (3 Replies)
Discussion started by: linuxnewbeee
3 Replies

4. Shell Programming and Scripting

Insert a line including Variable & Carriage Return / sed command as Variable

I want to instert Category:XXXXX into the 2. line something like this should work, but I have somewhere the wrong sytanx. something with the linebreak goes wrong: sed "2i\\${n}Category:$cat\n" Sample: Titel Blahh Blahh abllk sdhsd sjdhf Blahh Blah Blahh Blahh Should look like... (2 Replies)
Discussion started by: lowmaster
2 Replies

5. UNIX for Dummies Questions & Answers

sed insert command and variable expansion/command substitution

I know this script is crummy, but I was just messing around.. how do I get sed's insert command to allow variable expansion to show the filename? #!/bin/bash filename=`echo $0` /usr/bin/sed '/#include/ { i\ the filename is `$filename` }' $1 exit 0 (8 Replies)
Discussion started by: glev2005
8 Replies

6. Shell Programming and Scripting

bash variable (set via awk+sed) not working as expected

Hi! Been working on a script and I've been having a problem. I've finally narrowed it down to this variable I'm setting: servername=$(awk -v FS=\/ '{ print $7 } blah.txt | sed 's\/./-/g' | awk -v FS=\- '{print $1}')" This will essentially pare down a line like this: ... (7 Replies)
Discussion started by: creativedynamo
7 Replies

7. Shell Programming and Scripting

In bash script, how to assign output of a command to a variable while keeping tabs?

Hi, wondering if it's been asked before but didn't find matches from google. Basically I have this line: myvar=$(echo -e "a\tb") Now somehow the '\t' from the echo output gets replaced with white space and then stored in $myvar. It creates a problem for me later to use tab as delimiter to do... (2 Replies)
Discussion started by: birddie
2 Replies

8. Shell Programming and Scripting

Bash script set command to a variable

Hi, Will following set up work in bash script? I've got errors if assigning following binary command to a variable. But on the other hand, COMMAND="ls" works. Any explanation please? How can I assign binary command to a variable COMMAND then I can just call ${COMMAND}? COMMAND="rsync"... (3 Replies)
Discussion started by: hce
3 Replies

9. Shell Programming and Scripting

sed command not accepting variable in shell script

I am using a shell script in fedora linux. While calling to the shell I am also passing an argument (var1=0.77) like shown below sh gossip.sh var1=0.77 in the shell following command is written (which doesn't work) sed - i -e 's@prob=@prob="$var1";//@g' file.txt Actually i want the... (7 Replies)
Discussion started by: Fakhar Hassan
7 Replies

10. Shell Programming and Scripting

Executing sed command inside a bash script

I want to run commands inside a bash script. An example is I want to pass the command in a string as regexp as an argument to the script, then run sed on the bash variable sed.sh regexp sed.sh "-i \"s/<p>//g\"" then call sed "$regexp" $fl (3 Replies)
Discussion started by: Kangol
3 Replies
SED(1)								   User Commands							    SED(1)

NAME
sed - stream editor for filtering and transforming text SYNOPSIS
sed [OPTION]... {script-only-if-no-other-script} [input-file]... DESCRIPTION
Sed is a stream editor. A stream editor is used to perform basic text transformations on an input stream (a file or input from a pipe- line). While in some ways similar to an editor which permits scripted edits (such as ed), sed works by making only one pass over the input(s), and is consequently more efficient. But it is sed's ability to filter text in a pipeline which particularly distinguishes it from other types of editors. -n, --quiet, --silent suppress automatic printing of pattern space -e script, --expression=script add the script to the commands to be executed -f script-file, --file=script-file add the contents of script-file to the commands to be executed --follow-symlinks follow symlinks when processing in place -i[SUFFIX], --in-place[=SUFFIX] edit files in place (makes backup if extension supplied) -l N, --line-length=N specify the desired line-wrap length for the `l' command --posix disable all GNU extensions. -r, --regexp-extended use extended regular expressions in the script. -s, --separate consider files as separate rather than as a single continuous long stream. -u, --unbuffered load minimal amounts of data from the input files and flush the output buffers more often --help display this help and exit --version output version information and exit If no -e, --expression, -f, or --file option is given, then the first non-option argument is taken as the sed script to interpret. All remaining arguments are names of input files; if no input files are specified, then the standard input is read. E-mail bug reports to: bonzini@gnu.org . Be sure to include the word ``sed'' somewhere in the ``Subject:'' field. COMMAND SYNOPSIS
This is just a brief synopsis of sed commands to serve as a reminder to those who already know sed; other documentation (such as the tex- info document) must be consulted for fuller descriptions. Zero-address ``commands'' : label Label for b and t commands. #comment The comment extends until the next newline (or the end of a -e script fragment). } The closing bracket of a { } block. Zero- or One- address commands = Print the current line number. a text Append text, which has each embedded newline preceded by a backslash. i text Insert text, which has each embedded newline preceded by a backslash. q Immediately quit the sed script without processing any more input, except that if auto-print is not disabled the current pattern space will be printed. Q Immediately quit the sed script without processing any more input. r filename Append text read from filename. R filename Append a line read from filename. Commands which accept address ranges { Begin a block of commands (end with a }). b label Branch to label; if label is omitted, branch to end of script. t label If a s/// has done a successful substitution since the last input line was read and since the last t or T command, then branch to label; if label is omitted, branch to end of script. T label If no s/// has done a successful substitution since the last input line was read and since the last t or T command, then branch to label; if label is omitted, branch to end of script. c text Replace the selected lines with text, which has each embedded newline preceded by a backslash. d Delete pattern space. Start next cycle. D Delete up to the first embedded newline in the pattern space. Start next cycle, but skip reading from the input if there is still data in the pattern space. h H Copy/append pattern space to hold space. g G Copy/append hold space to pattern space. x Exchange the contents of the hold and pattern spaces. l List out the current line in a ``visually unambiguous'' form. n N Read/append the next line of input into the pattern space. p Print the current pattern space. P Print up to the first embedded newline of the current pattern space. s/regexp/replacement/ Attempt to match regexp against the pattern space. If successful, replace that portion matched with replacement. The replacement may contain the special character & to refer to that portion of the pattern space which matched, and the special escapes 1 through 9 to refer to the corresponding matching sub-expressions in the regexp. w filename Write the current pattern space to filename. W filename Write the first line of the current pattern space to filename. y/source/dest/ Transliterate the characters in the pattern space which appear in source to the corresponding character in dest. Addresses Sed commands can be given with no addresses, in which case the command will be executed for all input lines; with one address, in which case the command will only be executed for input lines which match that address; or with two addresses, in which case the command will be executed for all input lines which match the inclusive range of lines starting from the first address and continuing to the second address. Three things to note about address ranges: the syntax is addr1,addr2 (i.e., the addresses are separated by a comma); the line which addr1 matched will always be accepted, even if addr2 selects an earlier line; and if addr2 is a regexp, it will not be tested against the line that addr1 matched. After the address (or address-range), and before the command, a ! may be inserted, which specifies that the command shall only be executed if the address (or address-range) does not match. The following address types are supported: number Match only the specified line number. first~step Match every step'th line starting with line first. For example, ``sed -n 1~2p'' will print all the odd-numbered lines in the input stream, and the address 2~5 will match every fifth line, starting with the second. (This is an extension.) $ Match the last line. /regexp/ Match lines matching the regular expression regexp. cregexpc Match lines matching the regular expression regexp. The c may be any character. GNU sed also supports some special 2-address forms: 0,addr2 Start out in "matched first address" state, until addr2 is found. This is similar to 1,addr2, except that if addr2 matches the very first line of input the 0,addr2 form will be at the end of its range, whereas the 1,addr2 form will still be at the beginning of its range. addr1,+N Will match addr1 and the N lines following addr1. addr1,~N Will match addr1 and the lines following addr1 until the next line whose input line number is a multiple of N. REGULAR EXPRESSIONS
POSIX.2 BREs should be supported, but they aren't completely because of performance problems. The sequence in a regular expression matches the newline character, and similarly for a, , and other sequences. BUGS
E-mail bug reports to bonzini@gnu.org. Be sure to include the word ``sed'' somewhere in the ``Subject:'' field. Also, please include the output of ``sed --version'' in the body of your report if at all possible. COPYRIGHT
Copyright (C) 2003 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICU- LAR PURPOSE, to the extent permitted by law. SEE ALSO
awk(1), ed(1), grep(1), tr(1), perlre(1), sed.info, any of various books on sed, the sed FAQ (http://sed.sf.net/grabbag/tutorials/sed- faq.txt), http://sed.sf.net/grabbag/. The full documentation for sed is maintained as a Texinfo manual. If the info and sed programs are properly installed at your site, the command info sed should give you access to the complete manual. sed version 4.1.5 July 2010 SED(1)
All times are GMT -4. The time now is 12:54 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy