The action of replacing something with another thing.
The action of replacing something with another thing.
Questions tagged [substitution]
1879 questions
479
votes
3 answers
Substitute multiple whitespace with single whitespace in Python
I have this string:
mystring = 'Here is some text I wrote '
How can I substitute the double, triple (...) whitespace chracters with a single space, so that I get:
mystring = 'Here is some text I wrote'
creativz
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427
votes
3 answers
JavaScript - Replace all commas in a string
I have a string with multiple commas, and the string replace method will only change the first one:
var mystring = "this,is,a,test"
mystring.replace(",","newchar", -1)
Result: "thisnewcharis,a,test"
The documentation indicates that the default…
mike
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238
votes
14 answers
bash : Bad Substitution
#!/bin/bash
jobname="job_201312161447_0003"
jobname_pre=${jobname:0:16}
jobname_post=${jobname:17}
This bash script gives me Bad substitution error on ubuntu. Any help will be highly appreciated.
Arindam Choudhury
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187
votes
3 answers
Command substitution: backticks or dollar sign / paren enclosed?
What's the preferred way to do command substitution in bash?
I've always done it like this:
echo "Hello, `whoami`."
But recently, I've often seen it written like this:
echo "Hello, $(whoami)."
What's the preferred syntax, and why? Or are they…
Dagg Nabbit
- 75,346
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145
votes
4 answers
sed error: "invalid reference \1 on `s' command's RHS"
I run several substitution commands as the core of a colorize script for maven.
One of the sed commands uses a regular expression which works find in the shell as discussed here. The current (not working) implementation can be found here.
When I…
JJD
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137
votes
2 answers
How to avoid heredoc expanding variables?
I'm trying to create a script file using substitution string from ENV but want also to prevent some from escaping
export PLACEHOLDER1="myPlaceholder1Value"
sudo /bin/su -c "cat << EOF >…
TheCodeKiller
- 1,733
- 2
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84
votes
6 answers
sed substitution with Bash variables
I am trying to change the values in a text file using sed in a Bash script with the line,
sed 's/draw($prev_number;n_)/draw($number;n_)/g' file.txt > tmp
This will be in a for loop. Why is it not working?
csta
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70
votes
2 answers
Substitute with contents of register or lines range from elsewhere in file in Vim
I'm using Vim, and I want to substitute some placeholder text with a long string, that spans several lines, which is already written somewhere else in the file.
Is it possible to replace a pattern with the contents of a register? Something…
Paolo Tedesco
- 55,237
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63
votes
8 answers
Remove all newlines from inside a string
I'm trying to remove all newline characters from a string. I've read up on how to do it, but it seems that I for some reason am unable to do so. Here is step by step what I am doing:
string1 = "Hello \n World"
string2 = string1.strip('\n')
print…
LandonWO
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60
votes
9 answers
How can I use a variable in the replacement side of the Perl substitution operator?
I would like to do the following:
$find = "start (.*) end";
$replace = "foo \1 bar";
$var = "start middle end";
$var =~ s/$find/$replace/;
I would expect $var to contain "foo middle bar", but it does not work. Neither does:
$replace = 'foo \1…
Manu
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48
votes
7 answers
How to substitute text from files in git history?
I've always used an interface based git client (smartGit) and thus don't have much experience with the git console.
However, I now face the need to substitute a string in all .txt files from history (so, not erasing the whole file but just…
Tom
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38
votes
1 answer
replace newline character in bash variable?
I am trying to understand the "cdargs-bash.sh" script with cdargs packages. And I have a question about in the following function:
function _cdargs_get_dir ()
{
local bookmark extrapath
# if there is one exact match (possibly with extra path info…
yorua007
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38
votes
8 answers
How to repeat a command with substitution in Vim?
In Unix the ^ allows you to repeat a command with some text substituted for new text. For example:
csh% grep "stuff" file1 >> Results
grep "stuff" file1
csh% ^file1^file2^
grep "stuff" file2
csh%
Is there a Vim equivalent? There are a lot of times…
Whaledawg
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37
votes
2 answers
Why does my Bash code fail when I run it with 'sh'?
I have a line of code that works fine in my terminal:
for i in *.mp4; do echo ffmpeg -i "$i" "${i/.mp4/.mp3}"; done
Then I put the exact same line of code in a script myscript.sh:
#!/bin/sh
for i in *.mp4; do echo ffmpeg -i "$i" "${i/.mp4/.mp3}";…
WhatIsName
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32
votes
3 answers
Adding Line Break After pattern in VIM
I have a css file and I want to add an empty line after every }.
How can I do this in Vim?
Chalist
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