I am using Mac OS 10.9, currently I am having trouble to find out where does the specific environment coming from and knowing where it declares.
For example: I want to know where is the PATH being declared and set. Since it can be set anywhere in .bash_profile or .bashrc or .anyfile_and anywhere_that_set_it_and_declare_it. Now, what is the easiest way using bash to list all files where the PATH variable being assigned?
NOTE: there are correct answers by Jahid and others using grep. I accept that answer since it works as expected BUT, I am waiting for someone answer with much better speed. Because it will take forever to run grep -r with / at the end.
Like this:
grep -r -e "export PATH " -e "export PATH=" .
using "export PATH " with grep will deal with assignments having indentation between PATH and =
Note: . means current directory. You can replace it with a full path of a directory or if you want to search in the whole filesystem, replace it with /
Bash doesn't track provenance for variables, what I suggest is using grep to search for instances of the PATH variable, for example: $ grep -r PATH .
Related
I have a problem regarding an alias file in /etc/profile.d/. This isn't anything important. I'm just interested why it isn't working as expected.
So basically I have the file 00-alias.sh at the path mentioned above and I wanted to make a shortcut which reads a specific line of a file. So this is my code:
alias lnn='sed -n "${1}p" < "${2}"'
With that code I should be able to perform a command like
$ lnn 4 test.txt
However, this doesn't work. I simply get the error
-bash: : No such file or directory
Now I thought, ok, maybe relative paths aren't working because the file is located at the path /etc/profile.d/00-alias.sh
So I went ahead and made a new alias like
alias pwd2='echo $(pwd)'
Then updated the profile.d with
source /etc/profile.d/00-alias.sh
And just tried pwd2 but that echoed the path I was currently in. So in theory the file can be found with the command I wrote. I still tried to pass the file to my alias with absolute path like
$ lnn 4 /var/test.txt
Still same error as above.
But, if I enter the command of the alias in the terminal like
sed -n "4p" < test.txt
It works perfectly fine. No matter if I put quotes around test.txt
And here is another weird thing: If I write
alias lnn='sed -n "${1}p" < ${2}'
without the quotes around ${2} I get the error
-bash: ${2}: ambiguous redirect
In the terminal it works just fine...
So, what am I doing wrong? Does anyone have an idea on this? I'd love to know my mistake. But as I said, this isn't a real problem as I'm just curious why bash behaves like that.
Aliases in bash do not take parameters of any form. Save the pain and use a function instead.
function lnn() {
sed -n "${1}p" < "${2}"
}
Add the function to the file 00-alias.sh and source it once before calling the function from command-line.
source /etc/profile.d/00-alias.sh
lnn 4 test.txt
See more information at BashFAQ/80: How can I make an alias that takes an argument?
You can't. Aliases in bash are extremely rudimentary, and not really suitable to any serious purpose. The bash man page even says so explicitly:
An excerpt from the GNU bash man page, about aliases
.. There is no mechanism for using arguments in the replacement text. If arguments are needed, a shell function should be used.
On a side note the problem has nothing to do with relative paths (or) so, just remember aliases are not allowed in scripts. They're only allowed in interactive shells. If you're writing a script, always use a function instead.
I'm unable to use ls, bash.. any popular commands that are critical after changing the path.
I'm unsure what it was before (because I can't do vi command either).
I ran the first command, and realized the first one had a typo - not PATH, but I've typed PATh.
So I immediately ran the next one:
export PATH="/usr/local/bin:$PATh"
export PATH="/usr/local/bin:$PATH"
Then vi, ls, bash commands started to not work.
I did echo $PATH to see the PATH.
usr/local/bin:/usr/local/bin:/usr/local/bin:/usr/local/bin:
This is what I got. Any help is appreciated.
You should be able to source /etc/profile to reset your PATH variable, though it may step on a few other variables you've configured along the way. You could also just grep for the appropriate line from that to set PATH and redo that in your current environment
Also, you can always specify the full path to an executable you need in the interim. For example, if you wanted to use grep with the PATH in its current state you could use /bin/grep (or perhaps /usr/bin/grep depending your system)
1 > Try to load default .profile script
$ /bin/bash ./.profile
2 > Just Logout from current session
and Re-login it.
It appears you have "broken" your bash shell ~/.bash_profile script, because of the PATh typo. (The question explicitly states bash, so I'm answering in that context.)
Since the PATH is "broken", you will need to access your editor by using its fully qualified path.
/usr/bin/vi ~/.bash_profile
That should allow you to fix the PATh to be PATH.
If you find that you need to edit your PATH environment variable a lot, this little bash function can be helpful.
vipath() {
local tmpfile=$(mktemp /tmp/vipath-edit.XXXXXX)
echo "$PATH" | tr ':' '\n' > "$tmpfile"
vi "$tmpfile" && PATH=$(paste -s -d ':' "$tmpfile")
rm "$tmpfile"
}
Note: there are better ways to ensure the $tmpfile gets deleted that I did not use in this snippet. And on a multiuser system, there are better ways to make sure the temporary file is not located in a shared location.
If you want to add a directory location to your PATH, without adding duplicate locations, this little bash function can be helpful to prepend a directory location.
pathadd() {
if [ -d "$1" ] && [[ ! ":$PATH:" =~ ":$1:" ]]
then
PATH="$1:$PATH"
fi
}
I had the same in RHEL8, I did an export PATH for a certain directory and then no command worked anymore. I performed a faulty export PATH command probably.
I got messages like this:
>$ yum
bash: yum: command not found...
Install package 'yum' to provide command 'yum'? [N/y] n
Luckily I had some other similar systems where I could get the path from, so I did:
export PATH=/home/USER/.local/bin:/home/USER/bin:/usr/local/bin:/usr/bin:/usr/local/sbin:/usr/sbine
Change USER to your own.
To make it permanent: add to $HOME/.bashrc with:
export PATH=$PATH:<YOUR PATH HERE>
When you do export PATH="/usr/local/bin:$PATH" you are saying, set PATH to /usr/local/bin: plus whatever was in the PATH variable before. This essentially concatenates the string "/usr/local/bin:" with the old path. That is why your PATH repeats so much, you must have run that command a few times.
Try running this: export PATH="/usr/local/bin".
I am writing a shell script to sync to a github repo, kick off the build, then take the output file, rename it, and move it to a location where it can be seen by Apache.
It's the renaming of the file that I've got not the faintest how to do within a shell script (I have virtually no experience with shell scripts - my understanding
Compiler will create /var/espbuild/firstpart_1vXX_secondpart.bin
I need to move this file to:
/var/www/html/builds/espbuild/firstpart_1vXX_DATE_secondpart_postfix.bin
1vXX is the version number
DATE is the output of date +%m-%d
postfix is just a string.
I'm not really certain where to start for something like this - I'm sure there's a graceful way, since this is the kind of thing shell scripts are made for, but I know just about nothing about shell scripts.
Thanks in advance
You can get the result of a command into a variable by using $():
DATE=$(date +%m-%d)
Then just use it in the new filename:
INPUT=/var/espbuild/firstpart_1vXX_secondpart.bin
OUTPUT=/var/www/html/builds/espbuild/firstpart_1vXX_${DATE}_secondpart_postfix.bin
mv ${INPUT} ${OUTPUT}
Edit: To get out the version part, here's a quick example:
VERSION=$(grep -o 1v.. <<< ${INPUT})
Then OUTPUT should be set like:
OUTPUT=/var/www/html/builds/espbuild/firstpart_${VERSION}_${DATE}_secondpart_postfix.bin
You can use this in BASH:
f='/var/espbuild/firstpart_1vXX_secondpart.bin'
s="${f##*/}"
s2=${s##*_}
dest="/var/www/html/builds/espbuild/${s%_*}_$(date '+%m-%d')_${s2%.*}_postfix.bin"
echo "$dest"
/var/www/html/builds/espbuild/firstpart_1vXX_07-14_secondpart_postfix.bin
cp "$f" "$dest"
I'm using zsh terminal, and I'm trying to add a new entry (/home/david/pear/bin) to the PATH variable. I don't see a reference to the PATH variable in my ~/.zshrc file, but doing echo $PATH returns:
/usr/lib/lightdm/lightdm:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games
So I know that the path variable is being set somewhere. Where is the PATH variable set / modified for the zsh terminal?
Actually, using ZSH allows you to use special mapping of environment variables. So you can simply do:
# append
path+=('/home/david/pear/bin')
# or prepend
path=('/home/david/pear/bin' $path)
# export to sub-processes (make it inherited by child processes)
export PATH
For me that's a very neat feature which can be propagated to other variables.
Example:
typeset -T LD_LIBRARY_PATH ld_library_path :
Here, add this line to .zshrc:
export PATH=/home/david/pear/bin:$PATH
EDIT: This does work, but ony's answer above is better, as it takes advantage of the structured interface ZSH provides for variables like $PATH. This approach is standard for bash, but as far as I know, there is no reason to use it when ZSH provides better alternatives.
You can append to your PATH in a minimal fashion. No need for
parentheses unless you're appending more than one element. It also
usually doesn't need quotes. So the simple, short way to append is:
path+=/some/new/bin/dir
This lower-case syntax is using path as an array, yet also
affects its upper-case partner equivalent, PATH (to which it is
"bound" via typeset).
(Notice that no : is needed/wanted as a separator.)
Common interactive usage
Then the common pattern for testing a new script/executable becomes:
path+=$PWD/.
# or
path+=$PWD/bin
Common config usage
You can sprinkle path settings around your .zshrc (as above) and it will naturally lead to the earlier listed settings taking precedence (though you may occasionally still want to use the "prepend" form path=(/some/new/bin/dir $path)).
Related tidbits
Treating path this way (as an array) also means: no need to do a
rehash to get the newly pathed commands to be found.
Also take a look at vared path as a dynamic way to edit path
(and other things).
You may only be interested in path for this question, but since
we're talking about exports and arrays, note that
arrays generally cannot be exported.
You can even prevent PATH from taking on duplicate entries
(refer to
this
and this):
typeset -U path
PATH pre-populated
The reason your path already has some entries in it is due to your system shell files setting path for you. This is covered in a couple other posts:
Why and where the $PATH env variable is set?
Where is the source of $PATH? I cannot find it in .zshrc
one liner, without opening ~/.zshrc file
echo -n 'export PATH=~/bin:$PATH' >> ~/.zshrc
or
echo -n 'export PATH=$HOME/bin:$PATH' >> ~/.zshrc
To see the effect, do source ~/.zshrc in the same tab or open a new tab
Added path to ~/.zshrc
sudo vi ~/.zshrc
add new path
export PATH="$PATH:[NEW_DIRECTORY]/bin"
Update ~/.zshrc
Save ~/.zshrc
source ~/.zshrc
Check PATH
echo $PATH
OPTION 1: Add this line to ~/.zshrc:
export "PATH=$HOME/pear/bin:$PATH"
After that you need to run source ~/.zshrc in order your changes to take affect OR close this window and open a new one
OPTION 2: execute it inside the terminal console to add this path only to the current terminal window session. When you close the window/session, it will be lost.
If you are on macOS (I'm on Monterey 12.3.1), you may have been pulling your hair like I did metaphorically. These instructions above all worked for me within the terminal session, but I could never get it to persist no matter what I did with export. Moreover, I couldn't find the .zshrc anywhere.
Turns out Apple does it differently. The file you need to edit is etc/paths. You can simply sudo nano /etc/paths and add your path in a new line. Then simply restart terminal and voila.
for me PATH=$PATH:/path/to/file/bin
then export PATH worked.
to check echo $PATH . other solutions are adding the path temporarily.
I'm on Monterey 12.4 and the only way I could change the path was using the helper function. Editing text files in nano did diddly squat
# append
path+=('/foo/bar/yourpath')
# export to sub-processes
export PATH
to verify your new directory has been added correctly, you can use
print -l $path
thanks to the fact that its type is known to be an array
I am asking for general opinions on how to find files quickly.
One typical scenario is that I often need to grep some names from a PeopleNameFile.txt from Dir1. When I'm in a different directory, I am forced to grep the file with a long directory path. It would be nice to just do GREP "Warren Buffett" PeopleNameFile.txt.
BTW, I'm using Cygwin but I welcome any suggestions.
You can easily write a simple bash function in your ~/.bashrc:
function grnm() {
grep "$#" /path/to/peoplenamefile.txt
}
Then later on, at command line you can type:
$ grnm "Warren Buffet"
the nice thing is that you can actually include other grep parameters if you like as in:
$ grnm -i "warren buffet"
(The $ characters represent your shell prompt, not part of the command you type.)
When you edit the .bashrc file FOR THE FIRST TIME you may have to source it in your existing open cygwin windows:
$ source ~/.bashrc
But if you open a new window you should not have to do that.
Good luck, have fun
You can create script my_grep.sh and add it somewhere to you path, with content like this:
#!/bin/bash
grep $1 path/to/Dir1/PeopleNameFile.txt
than you just type
my_grep.sh "Warren Buffett"
also you can use alias and bash's function,
but this require to edit "~/.bashrc".
Simplest option would be to setup an alias which would grep for that file using the absolute path. Not sure whether cygwin allows aliases though.
Probably the most common way to do these kind of things is to use environment variables
e.g.
PNF='/very/long/path/PeopleNameFile.txt'
grep "Warren Buffett" $PNF