I'd like to generate some .env.example files for a dozen of projects.
In order to be smart and avoid tedious copy/pasting I thought about using the grep command.
How can I get from :
➜ app-service git:(chore/adding-env-example) ✗ c;grep -r "process\.env\." --exclude-d
ir=node_modules
./src/config/config_prod.js: level: process.env.LOG_LEVEL || 'error'
./src/config/config_prod.js: bypassToken: process.env.BYPASS_TOKEN || null
./src/config/config.js: port: process.env.APP_PORT || 3000,
./src/config/config.js: frontUrl: process.env.FRONT_URL,
./src/config/config.js: launchAppTopic: process.env.AWS_SNS_LAUNCH_APP_ARN
...
to
LOG_LEVEL=
BYPASS_TOKEN=
APP_PORT=
FRONT_URL=
AWS_SNS_LAUNCH_APP_ARN=
?
Retrieving the Environment Variables:
grep -oP "(?<=\.)[[:upper:]_]*(?=[ ,]*)"
Results:
LOG_LEVEL
BYPASS_TOKEN
APP_PORT
FRONT_URL
AWS_SNS_LAUNCH_APP_ARN
Retrieving the Environment Variables and adding =
sed -r -n 's|^.*\.([[:upper:]_]+).*$|\1=|p'
Results:
LOG_LEVEL=
BYPASS_TOKEN=
APP_PORT=
FRONT_URL=
AWS_SNS_LAUNCH_APP_ARN=
If you want to find all occurrences of an uppercase letter followed by uppercase letters and/or underscores, and then an =, and only if it is a word in itself:
grep -o -P '\b[A-Z][A-Z_]*='
Related
I am trying to use grep with the pwd command.
So, if i enter pwd, it shows me something like:
/home/hrq/my-project/
But, for purposes of a script i am making, i need to use it with grep, so it only prints what is after hrq/, so i need to hide my home folder always (the /home/hrq/) excerpt, and show only what is onwards (like, in this case, only my-project).
Is it possible?
I tried something like
pwd | grep -ov 'home', since i saw that the "-v" flag would be equivalent to the NOT operator, and combine it with the "-o" only matching flag. But it didn't work.
Given:
$ pwd
/home/foo/tmp
$ echo "$PWD"
/home/foo/tmp
Depending on what it is you really want to do, either of these is probably what you really should be using rather than trying to use grep:
$ basename "$PWD"
tmp
$ echo "${PWD#/home/foo/}"
tmp
Use grep -Po 'hrq/\K.*', for example:
grep -Po 'hrq/\K.*' <<< '/home/hrq/my-project/'
my-project/
Here, grep uses the following options:
-P : Use Perl regexes.
-o : Print the matches only (1 match per line), not the entire lines.
\K : Cause the regex engine to "keep" everything it had matched prior to the \K and not include it in the match. Specifically, ignore the preceding part of the regex when printing the match.
SEE ALSO:
grep manual
perlre - Perl regular expressions
I was searching for a change that included "foreach" so I used this Mercurial command:
$ hg grep -r "user(mjh) & public() & date(-30)" --diff -i foreach
and it does return the hits where "foreach" was added and removed.
However, I'd like to know the actual commit hashes too. If I add a template:
$ hg grep ... -T '{date|shortdate}\n{node|short}\n{desc|firstline}\n\n'
then I get the commit hash and description as expected, but then I don't see the changed files listed.
Is there a template to capture the output of hg grep? The {files} template lists the files associated with a commit, but that's not the actual grep output. Is there an iterable template keyword available for the grep results?
Please, re-read carefully hg help grep -v (-v is important option), note the following part (new and unexpected for me also)
The following keywords are supported in addition to the common
template
keywords and functions. See also 'hg help templates'.
change String. Character denoting insertion "+" or removal "-".
Available if "--diff" is specified.
lineno Integer. Line number of the match.
path String. Repository-absolute path of the file.
texts List of text chunks.
After it you'll be able to repeat (so-so, because some details will differ slightly) default output of grep in you template
>hg grep --diff -i -r 1166 to_try
>hg grep --diff -i -r 1166 -T "{path}:{rev}:{change}:{texts}\n" to_try
hggit/compat.py:1166:-: for args in parameters_to_try:
hggit/compat.py:1166:+: for (args, kwargs) in parameters_to_try:
and after replacing {rev} by {node|short}
>hg grep --diff -i -r 1166 -T "{path}:{node|short}:{change}:{texts}\n" to_try
hggit/compat.py:f6cef55e6aeb:-: for args in parameters_to_try:
hggit/compat.py:f6cef55e6aeb:+: for (args, kwargs) in parameters_to_try:
I've created a small function to allow me to grep through my command history on zsh. The command history 1 will display the entire command history. And running history 1 | egrep ls shows just those command containing ls.
So my function looks like this:
h() {
if [ -z "$*" ]
then
history 1
else
history 1 | egrep "$#"
fi
}
Unfortunately this only results in the following error message:
$ h ls
egrep: ls: No such file or directory
I'm at a loss as to what is wrong in my script. I've trie both grep and egrep to no avail.
What is the full path of grep or egrep?
It's possible that it's running in an alternate shell which has a different PATH set. Try using an explicit /usr/bin/grep or /usr/bin/egrep and see if that fixes anything.
Create a file history.zsh (slightly changed from the original):
#!/bin/zsh
h() {
if [ -z "$*" ]
then
history
else
history | fgrep "$*"
fi
}
Now source this file (so "h" will be refreshed):
. history.zsh
And call the new function:
$ h ls
30 h ls
31 ls
I've abandoned the function. Further reading on the subject of zsh history lead me to this very elegant solution that meets my needs. https://coderwall.com/p/jpj_6q
In a nutshell you add this to your .zshrc:
autoload -U up-line-or-beginning-search
autoload -U down-line-or-beginning-searc
zle -N up-line-or-beginning-search
zle -N down-line-or-beginning-search
bindkey "^[[A" up-line-or-beginning-search # Up
bindkey "^[[B" down-line-or-beginning-search # Down
Now your history can be searched by entering a partial term and using the up or down arrow keys to walk through the matches from your history file.
Okay I have a file that contains numbers like this:
L21479
What I am trying to do is use grep (or a similar tool) to find all the strings in a file that have the format:
L#####
The # will be the number. SO an L followed by 5 numbers.
Is this even possible in grep? Should I load the file and perform regex?
You can do this with grep, for example with the following command:
grep -E -o 'L[0-9]{5}' name_of_file
For example, given a file with the text:
kasdhflkashl143112343214L232134614
3L1431413543454L2342L3523269ufoidu
gl9983ugsdu8768IUHI/(JHKJASHD/(888
The command above will output:
L23213
L14314
L35232
If it is just in a single file, you can do something along the lines of:
grep -e 'L[0-9]{5}' filename
If you need to search all files in a directory for these strings:
find . -type f | xargs grep -e 'L[0-9]{5}'
I have a very large file 100Mb+ where all the content is on one line.
I wish to find a pattern in that file and a number of characters around that pattern.
For example I would like to call a command like the one below but where -A and -B are number of bytes not lines:
cat very_large_file | grep -A 100 -B 100 somepattern
So for a file containing content like this:
1234567890abcdefghijklmnopqrstuvwxyz
With a pattern of
890abc
and a before size of -B 3
and an after size of -A 3
I want it to return:
567890abcdef
Any tips would be great.
Many thanks.
You could try the -o option:
-o, --only-matching
Show only the part of a matching line that matches PATTERN.
and use a regular expression to match your pattern and the 3 preceding/following characters i.e.
grep -o -P ".{3}pattern.{3}" very_large_file
In the example you gave, it would be
echo "1234567890abcdefghijklmnopqrstuvwxyz" > tmp.txt
grep -o -P ".{3}890abc.{3}" tmp.txt
Another one with sed (you may need it on systems where GNU grep is not available):
sed -n '
s/.*\(...890abc...\).*/\1/p
' infile
Best way I can think of doing this is with a tiny Perl script.
#!/usr/bin/perl
$pattern = $ARGV[0];
$before = $ARGV[1];
$after = $ARGV[2];
while(<>) {
print $& if( /.{$before}$pattern.{$after}/ );
}
You would then execute it thusly:
cat very_large_file | ./myPerlScript.pl 890abc 3 3
EDIT: Dang, Paolo's solution is much easier. Oh well, viva la Perl!