I have a configuration file (gpsd.default) containing data with the following format:
# If you must specify a non-NMEA driver, uncomment and modify the next line
GPSD_SOCKET="/var/run/gpsd.sock"
GPSD_OPTIONS=""
GPS_DEVICES=""
I am making a change on the file with sed:
sed -i 's/^GPS_DEVICES="".*/GPS_DEVICES="dev/ttyUSB1"/' /etc/default/gpsd.default
or
sed -i '4s/^.*/GPS_DEVICES="dev/ttyUSB1"/' /etc/default/gpsd.default
The above sed command returns error:
sed: bad option in substitution expression
Because the new line contains "/" in its expression.
How to update my sed command to make it work?
This is because you are using a regex containing /, which is the same character sed uses as delimiter.
Just change the sed delimiter to another one, for example ~:
sed -i 's~^GPS_DEVICES="".*~GPS_DEVICES="dev/ttyUSB1"~' /etc/default/gpsd.default
By the way, since you are changing files in /etc, you may want to use -i.bak, so that the original file gets backed up. It is a good practice to prevent loss of important information.
You should update your sed command to this.
sed -i 's/^GPS_DEVICES=\"\".*/GPS_DEVICES=\"dev\/ttyUSB1\"/' /etc/default/gpsd.default
I have two sed command which includes in my cook.sh script. One command is
sed -E -i "s/^(\\\$mainDomain=\")[^\"]+(\";)$/\1$MainDomain\2/" /var/config.php
This is working fine.
But the below command which is almost same. But it is not working.
sed -E -i "s/^(\\\$authURI=\")[^\"]+(\";)$/\1$duo_auth\2/" /var/config.php
That give the below error message
sed: -e expression #1, char 36: unknown option to `s'
Any idea on this ?
The issue is likely due to your replacement variable $duo_auth having a un-escaped /, change the default sed separator from / to ~ as
sed -E -i "s~^(\\\$authURI=\")[^\"]+(\";)$~\1$duo_auth\2~" /var/config.php
Try it without -i for seeing if the replacement is as expected and put it back after confirmation.
Example:-
cat /var/config.php
<?php
$authURI="dev.digin.io";
now setting the variable
duo_auth="http://auth.uri.digin.io:3048/"
Now the replacement, without -i
sed -E "s~^(\\\$authURI=\")[^\"]+(\";)$~\1$duo_auth\2~" /var/config.php
<?php
$authURI="http://auth.uri.digin.io:3048/";
The problem is probably due to $duo_auth containing an unescaped /. This means that the sed editing script will have a syntax error.
You may pick any other character to use as a delimiter in the s/.../.../ command, for example #:
sed "s#....#....#"
Just make sure that you pick a character that is not ever going to turn up in either $duo_auth or $authURI.
While testing, I'd recommend that you avoid using in-place-editing (-i) with sed. Also, the -i switch is horribly non-portable between sed implementations (some requires an argument).
Instead, do the slightly more cumbersome
sed -e "s#...#...#" data.in >data.in.tmp && mv -f data.in.tmp data.in
While testing, check the data.in.tmp file before moving it.
What's the simplest way to do a find and replace for a given input string, say abc, and replace with another string, say XYZ in file /tmp/file.txt?
I am writting an app and using IronPython to execute commands through SSH — but I don't know Unix that well and don't know what to look for.
I have heard that Bash, apart from being a command line interface, can be a very powerful scripting language. So, if this is true, I assume you can perform actions like these.
Can I do it with bash, and what's the simplest (one line) script to achieve my goal?
The easiest way is to use sed (or perl):
sed -i -e 's/abc/XYZ/g' /tmp/file.txt
Which will invoke sed to do an in-place edit due to the -i option. This can be called from bash.
If you really really want to use just bash, then the following can work:
while IFS='' read -r a; do
echo "${a//abc/XYZ}"
done < /tmp/file.txt > /tmp/file.txt.t
mv /tmp/file.txt{.t,}
This loops over each line, doing a substitution, and writing to a temporary file (don't want to clobber the input). The move at the end just moves temporary to the original name. (For robustness and security, the temporary file name should not be static or predictable, but let's not go there.)
For Mac users:
sed -i '' 's/abc/XYZ/g' /tmp/file.txt
(See the comment below why)
File manipulation isn't normally done by Bash, but by programs invoked by Bash, e.g.:
perl -pi -e 's/abc/XYZ/g' /tmp/file.txt
The -i flag tells it to do an in-place replacement.
See man perlrun for more details, including how to take a backup of the original file.
I was surprised when I stumbled over this...
There is a replace command which ships with the "mysql-server" package, so if you have installed it try it out:
# replace string abc to XYZ in files
replace "abc" "XYZ" -- file.txt file2.txt file3.txt
# or pipe an echo to replace
echo "abcdef" |replace "abc" "XYZ"
See man replace for more on this.
This is an old post but for anyone wanting to use variables as #centurian said the single quotes mean nothing will be expanded.
A simple way to get variables in is to do string concatenation since this is done by juxtaposition in bash the following should work:
sed -i -e "s/$var1/$var2/g" /tmp/file.txt
Bash, like other shells, is just a tool for coordinating other commands. Typically you would try to use standard UNIX commands, but you can of course use Bash to invoke anything, including your own compiled programs, other shell scripts, Python and Perl scripts etc.
In this case, there are a couple of ways to do it.
If you want to read a file, and write it to another file, doing search/replace as you go, use sed:
sed 's/abc/XYZ/g' <infile >outfile
If you want to edit the file in place (as if opening the file in an editor, editing it, then saving it) supply instructions to the line editor 'ex'
echo "%s/abc/XYZ/g
w
q
" | ex file
Example is like vi without the fullscreen mode. You can give it the same commands you would at vi's : prompt.
I found this thread among others and I agree it contains the most complete answers so I'm adding mine too:
sed and ed are so useful...by hand.
Look at this code from #Johnny:
sed -i -e 's/abc/XYZ/g' /tmp/file.txt
When my restriction is to use it in a shell script, no variable can be used inside in place of "abc" or "XYZ". The BashFAQ seems to agree with what I understand at least. So, I can't use:
x='abc'
y='XYZ'
sed -i -e 's/$x/$y/g' /tmp/file.txt
#or,
sed -i -e "s/$x/$y/g" /tmp/file.txt
but, what can we do? As, #Johnny said use a while read... but, unfortunately that's not the end of the story. The following worked well with me:
#edit user's virtual domain
result=
#if nullglob is set then, unset it temporarily
is_nullglob=$( shopt -s | egrep -i '*nullglob' )
if [[ is_nullglob ]]; then
shopt -u nullglob
fi
while IFS= read -r line; do
line="${line//'<servername>'/$server}"
line="${line//'<serveralias>'/$alias}"
line="${line//'<user>'/$user}"
line="${line//'<group>'/$group}"
result="$result""$line"'\n'
done < $tmp
echo -e $result > $tmp
#if nullglob was set then, re-enable it
if [[ is_nullglob ]]; then
shopt -s nullglob
fi
#move user's virtual domain to Apache 2 domain directory
......
As one can see if nullglob is set then, it behaves strangely when there is a string containing a * as in:
<VirtualHost *:80>
ServerName www.example.com
which becomes
<VirtualHost ServerName www.example.com
there is no ending angle bracket and Apache2 can't even load.
This kind of parsing should be slower than one-hit search and replace but, as you already saw, there are four variables for four different search patterns working out of one parse cycle.
The most suitable solution I can think of with the given assumptions of the problem.
You can use sed:
sed -i 's/abc/XYZ/gi' /tmp/file.txt
You can use find and sed if you don't know your filename:
find ./ -type f -exec sed -i 's/abc/XYZ/gi' {} \;
Find and replace in all Python files:
find ./ -iname "*.py" -type f -exec sed -i 's/abc/XYZ/gi' {} \;
Be careful if you replace URLs with "/" character.
An example of how to do it:
sed -i "s%http://domain.com%http://www.domain.com/folder/%g" "test.txt"
Extracted from: http://www.sysadmit.com/2015/07/linux-reemplazar-texto-en-archivos-con-sed.html
If the file you are working on is not so big, and temporarily storing it in a variable is no problem, then you can use Bash string substitution on the whole file at once - there's no need to go over it line by line:
file_contents=$(</tmp/file.txt)
echo "${file_contents//abc/XYZ}" > /tmp/file.txt
The whole file contents will be treated as one long string, including linebreaks.
XYZ can be a variable eg $replacement, and one advantage of not using sed here is that you need not be concerned that the search or replace string might contain the sed pattern delimiter character (usually, but not necessarily, /). A disadvantage is not being able to use regular expressions or any of sed's more sophisticated operations.
You may also use the ed command to do in-file search and replace:
# delete all lines matching foobar
ed -s test.txt <<< $'g/foobar/d\nw'
See more in "Editing files via scripts with ed".
To edit text in the file non-interactively, you need in-place text editor such as vim.
Here is simple example how to use it from the command line:
vim -esnc '%s/foo/bar/g|:wq' file.txt
This is equivalent to #slim answer of ex editor which is basically the same thing.
Here are few ex practical examples.
Replacing text foo with bar in the file:
ex -s +%s/foo/bar/ge -cwq file.txt
Removing trailing whitespaces for multiple files:
ex +'bufdo!%s/\s\+$//e' -cxa *.txt
Troubleshooting (when terminal is stuck):
Add -V1 param to show verbose messages.
Force quit by: -cwq!.
See also:
How to edit files non-interactively (e.g. in pipeline)? at Vi SE
Try the following shell command:
find ./ -type f -name "file*.txt" | xargs sed -i -e 's/abc/xyz/g'
You can use python within the bash script too. I didn't have much success with some of the top answers here, and found this to work without the need for loops:
#!/bin/bash
python
filetosearch = '/home/ubuntu/ip_table.txt'
texttoreplace = 'tcp443'
texttoinsert = 'udp1194'
s = open(filetosearch).read()
s = s.replace(texttoreplace, texttoinsert)
f = open(filetosearch, 'w')
f.write(s)
f.close()
quit()
Simplest way to replace multiple text in a file using sed command
Command -
sed -i 's#a/b/c#D/E#g;s#/x/y/z#D:/X#g;' filename
In the above command s#a/b/c#D/E#g where I am replacing a/b/c with D/E and then after the ; we again doing the same thing
You can use rpl command. For example you want to change domain name in whole php project.
rpl -ivRpd -x'.php' 'old.domain.name' 'new.domain.name' ./path_to_your_project_folder/
This is not clear bash of cause, but it's a very quick and usefull. :)
For MAC users in case you don't read the comments :)
As mentioned by #Austin, if you get the Invalid command code error
For the in-place replacements BSD sed requires a file extension after the -i flag to save to a backup file with given extension.
sed -i '.bak' 's/find/replace' /file.txt
You can use '' empty string if you want to skip backup.
sed -i '' 's/find/replace' /file.txt
All merit to #Austin
Open file using vim editor. In command mode
:%s/abc/xyz/g
This is the simplest
In case of doing changes in multiple files together we can do in a single line as:-
user_name='whoami'
for file in file1.txt file2.txt file3.txt; do sed -i -e 's/default_user/${user_name}/g' $file; done
Added if in case could be useful.
Having
DEST_PATH='/var/www/clones'
site='xyz.com'
sed -i -e "s/\$log_path\s=\s'\(.*\)'/\$log_path = '$DEST_PATH\/$site\/logs'/" $DEST_PATH/$site/configuration.php
The problem is the forward slashes in first variable, because this is what is being processed and returns error:
sed -i -e "s/\$log_path\s=\s'\(.*\)'/\$log_path = '/var/www/clones\/xyz.com\/logs'/" configuration.php
When this is what actually should be run:
sed -i -e "s/\$log_path\s=\s'\(.*\)'/\$log_path = '\/var\/www\/clones\/xyz.com\/logs'/" configuration.php
So I know, I could replace all the / inside $DEST_PATH, and run the sed again, but I was wondering if you know or can think of any other/better way of doing so. Ideally, maybe having sed automatically escape the '$DEST_PATH/$site/logs' if possible.
Are you using a modern enough version of sed (e.g., GNU sed)? Then you are not required to use / to separate pattern and substitution. Any character will do.
E.g., you can use
s,pattern,substitution,
instead of
s/pattern/substitution/
I have a file, and I am trying to use bask to replace all the contents of a substring with a path.
I can use the command:
sed -i s/{WORKSPACE}/$MYVARIABLE/g /var/lib/jenkins/jobs/MY-JOB/workspace/config/params.ini
My config/params.ini looks like:
[folders]
folder1 = {WORKSPACE}/subfolder1
folder2 = {WORKSPACE}/subfolder2
however, when $MYVARIABLE is a path, it fails (containing slashes), the sed command fails with:
sed: -e expression #1, char 16: unknown option to `s'
When I run through it manually, I see that the $MYVARIABLE needs to have it's path-slashes escaped. How can I modify my sed command to incorporate an escaped version of $MYVARIABLE?
There's nothing saying you have to use / as your delimiter. sed will use (almost) anything you stick in there. I have a tendency to use |, since that never (rarely?) appears in a path.
sridhar#century:~> export boong=FLEAK
sridhar#century:~> echo $PATH | sed "s|/bin|/$boong|g"
~/FLEAK:/usr/local/FLEAK:/usr/local/sbin:/usr/local/games:/FLEAK:/sbin:/usr/FLEAK:/usr/sbin:/usr/games:/usr/lib/lightdm/lightdm:/home/oracle/app/oracle/product/12.1.0/server_1/FLEAK
sridhar#century:~>
Using double-quotes will allow the shell to do the variable-substitution.
Just escape the $ sign, and use a different delimiter:
sed -i 's;{WORKSPACE};\$MYVARIABLE;g' your_file