Makefile's targets are available by completion on Linux but, AFAICS, not on Mac OS (10.8.5).
Is it possible to get completion working with this OS?
This seems to achieve simple bash completions for me on El Capitan:
# .bashrc
function _makefile_targets {
local curr_arg;
local targets;
# Find makefile targets available in the current directory
targets=''
if [[ -e "$(pwd)/Makefile" ]]; then
targets=$( \
grep -oE '^[a-zA-Z0-9_-]+:' Makefile \
| sed 's/://' \
| tr '\n' ' ' \
)
fi
# Filter targets based on user input to the bash completion
curr_arg=${COMP_WORDS[COMP_CWORD]}
COMPREPLY=( $(compgen -W "${targets[#]}" -- $curr_arg ) );
}
complete -F _makefile_targets make
Here's how this works:
complete -F [function name] [command name] -- this bash builtin register a new completion for [command name] which is generated by the bash function [function name]. So in my code above, if you type make [TAB][TAB] into your shell, you'll trigger the _makefile_targets() function.
if [[ -e "$(pwd)/Makefile" ]]; then -- make sure there's a Makefile in the current directory, otherwise don't try a bash completion.
grep -oE '^[a-zA-Z0-9_-]+:' Makefile -- filter every line of Makefile using the regex for a target name like "test:". -o means only return the part of the line that matches. For example, given a Makefile target like "test: build package", only "test:" will be returned
| sed 's/://' -- taking the grep results, remove the colon from the end of line
| tr '\n' ' ' -- smoosh all targets onto one line, separated by one space
Inside a bash completion function, complete sets several environment variables for you. COMP_WORDS is an array of the list of available bash completion choises based on what the user typed. COMP_CWORD is the index of the currently selected word.
Another very magical builtin compgen will take a list of space separately strings and filter them using the currently selected word. I'm not at all clear how that works.
So, the bottom line is that the last two lines in the function filter our list of makefile targets (stored inside $targets) and shoves them into an array COMPREPLY. The bash completion reads and displays COMPREPLY as choices in the shell.
Inspired by:
https://gist.github.com/tlrobinson/1073865
http://www.thegeekstuff.com/2013/12/bash-completion-complete/ (Esp 9.)
This worked for me on Catalina in the standard zsh terminal
Edit the file named .zshrc in you home directory this can be done with this command in the terminal nano ~/.zshrc
Add the following lines
zstyle ':completion:*:*:make:*' tag-order 'targets'
autoload -U compinit && compinit
exit and save by pressing ctrl + x and then save Y
For macOS Monterey, the following works:
Edit the .zprofile file in your home directory. This can be done with a text editor. Path: ~/.zprofile
Add the following lines to the end of the file:
zstyle ':completion:*:*:make:*' tag-order 'targets'
autoload -Uz compinit && compinit
After that, everything works correctly, tips work when you press TAB.
This method does not display anything extra when entering the terminal, unlike the methods indicated above.
If you use bash and homebrew:
brew install bash-completion
follow their documentation:
Add the following line to your ~/.bash_profile:
[[ -r "$(brew --prefix)/etc/profile.d/bash_completion.sh" ]] && . "$(brew --prefix)/etc/profile.d/bash_completion.sh"
restart your terminal or
source ~/.bash_profile
Bash tab completion adds extra space after the first completion which stops further completion if the compeletion target is a file in multi-level folders.
For example, I have a file in the path ~/Documents/foo/bar.txt, and I want to list it.
I face the following problem, when input
a#b:~$ls Docu <TAB>
I get
a#b:~$ls Documents |(<-this is the cursor, so there is an extra space afer Documents)
So I cannot further tab complete. I have to backspace to delete the extra space.
Normally I want to get:
a#b:~$ls Docu <TAB>
a#b:~$ls Documents/ <TAB>
a#b:~$ls Documents/foo/ <TAB>
a#b:~$ls Documents/foo/bar.txt
Just for the record: There is also a bug in the adobereader-enu (acroread) package that breaks bash completion. In this case you can just delete the symlink:
rm /etc/bash_completion.d/acroread.sh
See also: https://bugs.launchpad.net/ubuntu/+source/acroread/+bug/769866
I have had this same problem with my bash completion in both Ubuntu 11.10 and 12.04. I found that I was able to get many commands to start working correctly by editing /etc/bash_completion. Specifically, I commented out the following section:
####
# makeinfo and texi2dvi are defined elsewhere.
#
#for i in a2ps awk bash bc bison cat colordiff cp csplit \
# curl cut date df diff dir du enscript env expand fmt fold gperf gprof \
# grep grub head indent irb ld ldd less ln ls m4 md5sum mkdir mkfifo mknod \
# mv netstat nl nm objcopy objdump od paste patch pr ptx readelf rm rmdir \
# sed seq sha{,1,224,256,384,512}sum shar sort split strip tac tail tee \
# texindex touch tr uname unexpand uniq units vdir wc wget who; do
# have $i && complete -F _longopt -o default $i
#done
Now ls works well again. I have not figured out yet why mv is still mis-behaving.
This has been answered here at askubuntu. It is related to the bug here
Relevant answer from the above thread:
edit /etc/bash_completion line 1587, change default to filenames (make a backup first).
i also got around the problem by changing
_filedir with _filedir_pdf
in /etc/bash_completion.d/acroread.sh
(Ubuntu 12.04)
acroread bash completion changes the _filedir function thereby altering the behaviour of a lot of other alsobash completion functions
The GNU version of rm has a cool -I flag. From the manpage:
-I prompt once before removing more than three files, or when removing recursively. Less
intrusive than -i, while still giving protection against most mistakes
Macs don't:
$ rm -I scratch
rm: illegal option -- I
usage: rm [-f | -i] [-dPRrvW] file ...
unlink file
Sometimes people have coreutils (the GNU version) installed on Macs and sometimes they don't. Is there a way to detect this command line flag before proceeding? I'd like to have something like this in my bash_profile:
if [ has_gnu_rm_version ]; then
alias rm="rm -I"
fi
strings /bin/rm | grep -q 'GNU coreutils'
if $? is 0, it is coreutils
I would recommend not starting down this road at all. Target your scripts to be as portable as possible, and only rely on flags/options/behaviors you can count on. Shell scripting is hard enough - why add more room for error?
To get a sense of the kind of thing I have in mind, check out Ryan Tomayko's Shell Haters talk. He also has a very well-organized page with links to POSIX descriptions of shell features and utilities. Here's rm, for example.
I'd say test the output of rm -I on a temp file, if it passes then use the alias
touch /tmp/my_core_util_check
if rm -I /tmp/my_core_util_check > /dev/null 2>&1 ; then
alias rm="rm -I"
else
rm /tmp/my_core_util_check;
fi
You could always ask rm its version with --version and check to see if it says gnu or coreutils like this:
rm --version 2>&1 | grep -i gnu &> /dev/null
[ $? -eq 0 ] && alias rm="rm -I"
how about something like this?
#!/bin/bash
rm -I &> /dev/null
if [ "$?" == "0" ]; then
echo coreutils detected
else
echo bsd version detected
fi
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On Linux, the readlink utility accepts an option -f that follows additional links. This doesn't seem to work on Mac and possibly BSD based systems. What would the equivalent be?
Here's some debug information:
$ which readlink; readlink -f
/usr/bin/readlink
readlink: illegal option -f
usage: readlink [-n] [file ...]
MacPorts and Homebrew provide a coreutils package containing greadlink (GNU readlink). Credit to Michael Kallweitt post in mackb.com.
brew install coreutils
greadlink -f file.txt
readlink -f does two things:
It iterates along a sequence of symlinks until it finds an actual file.
It returns that file's canonicalized name—i.e., its absolute pathname.
If you want to, you can just build a shell script that uses vanilla readlink behavior to achieve the same thing. Here's an example. Obviously you could insert this in your own script where you'd like to call readlink -f
#!/bin/sh
TARGET_FILE=$1
cd `dirname $TARGET_FILE`
TARGET_FILE=`basename $TARGET_FILE`
# Iterate down a (possible) chain of symlinks
while [ -L "$TARGET_FILE" ]
do
TARGET_FILE=`readlink $TARGET_FILE`
cd `dirname $TARGET_FILE`
TARGET_FILE=`basename $TARGET_FILE`
done
# Compute the canonicalized name by finding the physical path
# for the directory we're in and appending the target file.
PHYS_DIR=`pwd -P`
RESULT=$PHYS_DIR/$TARGET_FILE
echo $RESULT
Note that this doesn't include any error handling. Of particular importance, it doesn't detect symlink cycles. A simple way to do this would be to count the number of times you go around the loop and fail if you hit an improbably large number, such as 1,000.
EDITED to use pwd -P instead of $PWD.
Note that this script expects to be called like ./script_name filename, no -f, change $1 to $2 if you want to be able to use with -f filename like GNU readlink.
You may be interested in realpath(3), or Python's os.path.realpath. The two aren't exactly the same; the C library call requires that intermediary path components exist, while the Python version does not.
$ pwd
/tmp/foo
$ ls -l
total 16
-rw-r--r-- 1 miles wheel 0 Jul 11 21:08 a
lrwxr-xr-x 1 miles wheel 1 Jul 11 20:49 b -> a
lrwxr-xr-x 1 miles wheel 1 Jul 11 20:49 c -> b
$ python -c 'import os,sys;print(os.path.realpath(sys.argv[1]))' c
/private/tmp/foo/a
I know you said you'd prefer something more lightweight than another scripting language, but just in case compiling a binary is insufferable, you can use Python and ctypes (available on Mac OS X 10.5) to wrap the library call:
#!/usr/bin/python
import ctypes, sys
libc = ctypes.CDLL('libc.dylib')
libc.realpath.restype = ctypes.c_char_p
libc.__error.restype = ctypes.POINTER(ctypes.c_int)
libc.strerror.restype = ctypes.c_char_p
def realpath(path):
buffer = ctypes.create_string_buffer(1024) # PATH_MAX
if libc.realpath(path, buffer):
return buffer.value
else:
errno = libc.__error().contents.value
raise OSError(errno, "%s: %s" % (libc.strerror(errno), buffer.value))
if __name__ == '__main__':
print realpath(sys.argv[1])
Ironically, the C version of this script ought to be shorter. :)
A simple one-liner in perl that's sure to work almost everywhere without any external dependencies:
perl -MCwd -e 'print Cwd::abs_path shift' ~/non-absolute/file
Will dereference symlinks.
Usage in a script could be like this:
readlinkf(){ perl -MCwd -e 'print Cwd::abs_path shift' "$1";}
ABSPATH="$(readlinkf ./non-absolute/file)"
You might need both a portable, pure shell implementation, and unit-test coverage, as the number of edge-cases for something like this is non-trivial.
See my project on Github for tests and full code. What follows is a synopsis of the implementation:
As Keith Smith astutely points out, readlink -f does two things: 1) resolves symlinks recursively, and 2) canonicalizes the result, hence:
realpath() {
canonicalize_path "$(resolve_symlinks "$1")"
}
First, the symlink resolver implementation:
resolve_symlinks() {
local dir_context path
path=$(readlink -- "$1")
if [ $? -eq 0 ]; then
dir_context=$(dirname -- "$1")
resolve_symlinks "$(_prepend_path_if_relative "$dir_context" "$path")"
else
printf '%s\n' "$1"
fi
}
_prepend_path_if_relative() {
case "$2" in
/* ) printf '%s\n' "$2" ;;
* ) printf '%s\n' "$1/$2" ;;
esac
}
Note that this is a slightly simplified version of the full implementation. The full implementation adds a small check for symlink cycles, as well as massages the output a bit.
Finally, the function for canonicalizing a path:
canonicalize_path() {
if [ -d "$1" ]; then
_canonicalize_dir_path "$1"
else
_canonicalize_file_path "$1"
fi
}
_canonicalize_dir_path() {
(cd "$1" 2>/dev/null && pwd -P)
}
_canonicalize_file_path() {
local dir file
dir=$(dirname -- "$1")
file=$(basename -- "$1")
(cd "$dir" 2>/dev/null && printf '%s/%s\n' "$(pwd -P)" "$file")
}
That's it, more or less. Simple enough to paste into your script, but tricky enough that you'd be crazy to rely on any code that doesn't have unit tests for your use cases.
Install homebrew
Run "brew install coreutils"
Run "greadlink -f path"
greadlink is the gnu readlink that implements -f. You can use macports or others as well, I prefer homebrew.
I made a script called realpath personally which looks a little something like:
#!/usr/bin/env python
import os, sys
print(os.path.realpath(sys.argv[1]))
What about this?
function readlink() {
DIR="${1%/*}"
(cd "$DIR" && echo "$(pwd -P)")
}
A lazy way that works for me,
$ brew install coreutils
$ ln -s /usr/local/bin/greadlink /usr/local/bin/readlink
$ which readlink
/usr/local/bin/readlink
/usr/bin/readlink
Implementation
Install brew
Follow the instructions at https://brew.sh/
Install the coreutils package
brew install coreutils
Create an Alias or Symlink
3a. Create an an alias (per user)
You can place your alias in ~/.bashrc, ~/.bash_profile, or wherever you are used to keeping your bash aliases. I personally keep mine in ~/.bashrc
alias readlink=greadlink
3b. Create a symbolic link (system wide)
ln -s /usr/local/bin/greadlink /usr/local/bin/readlink (credit: Izana)
This will create a symbolic link in /usr/local/bin while keeping the original readlink binary in tact. It works because the search for readlink will return 2 results. But the second in /usr/local/bin will take precedence.
e.g. which readlink
To undo this change simply unlink /usr/local/bin/readlink
Additional Tools
You can create similar aliases or symlinks for other coreutils such as gmv, gdu, gdf, and so on. But beware that the GNU behavior on a mac machine may be confusing to others used to working with native coreutils, or may behave in unexpected ways on your mac system.
Explanation
coreutils is a brew package that installs GNU/Linux core utilities which correspond to the Mac OSX implementation of them so that you can use those
You may find programs or utilties on your mac osx system which seem similar to Linux coreutils ("Core Utilities") yet they differ in some ways (such as having different flags).
This is because the Mac OSX implementation of these tools are different. To get the original GNU/Linux-like behavior you can install the coreutils package via the brew package management system.
This will install corresponding core utilities, prefixed by g. E.g. for readlink, you will find a corresponding greadlink program.
In order to make readlink perform like the GNU readlink (greadlink) implementation, you can create a simple alias or symbolic link after you install coreutils.
FreeBSD and OSX have a version of statderived from NetBSD.
You can adjust the output with format switches (see the manual pages at the links above).
% cd /service
% ls -tal
drwxr-xr-x 22 root wheel 27 Aug 25 10:41 ..
drwx------ 3 root wheel 8 Jun 30 13:59 .s6-svscan
drwxr-xr-x 3 root wheel 5 Jun 30 13:34 .
lrwxr-xr-x 1 root wheel 30 Dec 13 2013 clockspeed-adjust -> /var/service/clockspeed-adjust
lrwxr-xr-x 1 root wheel 29 Dec 13 2013 clockspeed-speed -> /var/service/clockspeed-speed
% stat -f%R clockspeed-adjust
/var/service/clockspeed-adjust
% stat -f%Y clockspeed-adjust
/var/service/clockspeed-adjust
Some OS X versions of stat may lack the -f%R option for formats. In this case -stat -f%Y may suffice. The -f%Y option will show the target of a symlink, whereas -f%R shows the absolute pathname corresponding to the file.
EDIT:
If you're able to use Perl (Darwin/OS X comes installed with recent verions of perl) then:
perl -MCwd=abs_path -le 'print abs_path readlink(shift);' linkedfile.txt
will work.
The easiest way to solve this problem and enable the functionality of readlink on Mac w/ Homebrew installed or FreeBSD is to install 'coreutils' package. May also be necessary on certain Linux distributions and other POSIX OS.
For example, in FreeBSD 11, I installed by invoking:
# pkg install coreutils
On MacOS with Homebrew, the command would be:
$ brew install coreutils
Not really sure why the other answers are so complicated, that's all there is to it. The files aren't in a different place, they're just not installed yet.
Here is a portable shell function that should work in ANY Bourne comparable shell.
It will resolve the relative path punctuation ".. or ." and dereference symbolic links.
If for some reason you do not have a realpath(1) command, or readlink(1) this can be aliased.
which realpath || alias realpath='real_path'
Enjoy:
real_path () {
OIFS=$IFS
IFS='/'
for I in $1
do
# Resolve relative path punctuation.
if [ "$I" = "." ] || [ -z "$I" ]
then continue
elif [ "$I" = ".." ]
then FOO="${FOO%%/${FOO##*/}}"
continue
else FOO="${FOO}/${I}"
fi
## Resolve symbolic links
if [ -h "$FOO" ]
then
IFS=$OIFS
set `ls -l "$FOO"`
while shift ;
do
if [ "$1" = "->" ]
then FOO=$2
shift $#
break
fi
done
IFS='/'
fi
done
IFS=$OIFS
echo "$FOO"
}
also, just in case anybody is interested here is how to implement basename and dirname in 100% pure shell code:
## http://www.opengroup.org/onlinepubs/000095399/functions/dirname.html
# the dir name excludes the least portion behind the last slash.
dir_name () {
echo "${1%/*}"
}
## http://www.opengroup.org/onlinepubs/000095399/functions/basename.html
# the base name excludes the greatest portion in front of the last slash.
base_name () {
echo "${1##*/}"
}
You can find updated version of this shell code at my google site: http://sites.google.com/site/jdisnard/realpath
EDIT:
This code is licensed under the terms of the 2-clause (freeBSD style) license.
A copy of the license may be found by following the above hyperlink to my site.
Begin Update
This is such a frequent problem that we have put together a Bash 4 library for free use (MIT License) called realpath-lib. This is designed to emulate readlink -f by default and includes two test suites to verify (1) that it works for a given unix system and (2) against readlink -f if installed (but this is not required). Additionally, it can be used to investigate, identify and unwind deep, broken symlinks and circular references, so it can be a useful tool for diagnosing deeply-nested physical or symbolic directory and file problems. It can be found at github.com or bitbucket.org.
End Update
Another very compact and efficient solution that does not rely on anything but Bash is:
function get_realpath() {
[[ ! -f "$1" ]] && return 1 # failure : file does not exist.
[[ -n "$no_symlinks" ]] && local pwdp='pwd -P' || local pwdp='pwd' # do symlinks.
echo "$( cd "$( echo "${1%/*}" )" 2>/dev/null; $pwdp )"/"${1##*/}" # echo result.
return 0 # success
}
This also includes an environment setting no_symlinks that provides the ability to resolve symlinks to the physical system. As long as no_symlinks is set to something, ie no_symlinks='on' then symlinks will be resolved to the physical system. Otherwise they will be applied (the default setting).
This should work on any system that provides Bash, and will return a Bash compatible exit code for testing purposes.
There are already a lot of answers, but none worked for me... So this is what I'm using now.
readlink_f() {
local target="$1"
[ -f "$target" ] || return 1 #no nofile
while [ -L "$target" ]; do
target="$(readlink "$target")"
done
echo "$(cd "$(dirname "$target")"; pwd -P)/$target"
}
Since my work is used by people with non-BSD Linux as well as macOS, I've opted for using these aliases in our build scripts (sed included since it has similar issues):
##
# If you're running macOS, use homebrew to install greadlink/gsed first:
# brew install coreutils
#
# Example use:
# # Gets the directory of the currently running script
# dotfilesDir=$(dirname "$(globalReadlink -fm "$0")")
# alias al='pico ${dotfilesDir}/aliases.local'
##
function globalReadlink () {
# Use greadlink if on macOS; otherwise use normal readlink
if [[ $OSTYPE == darwin* ]]; then
greadlink "$#"
else
readlink "$#"
fi
}
function globalSed () {
# Use gsed if on macOS; otherwise use normal sed
if [[ $OSTYPE == darwin* ]]; then
gsed "$#"
else
sed "$#"
fi
}
Optional check you could add to automatically install homebrew + coreutils dependencies:
if [[ "$OSTYPE" == "darwin"* ]]; then
# Install brew if needed
if [ -z "$(which brew)" ]; then
/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)";
fi
# Check for coreutils
if [ -z "$(brew ls coreutils)" ]; then
brew install coreutils
fi
fi
I suppose to be truly "global" it needs to check others...but that probably comes close to the 80/20 mark.
POSIX compliant readlink -f implementation for POSIX shell scripts
https://github.com/ko1nksm/readlinkf
This is POSIX compliant (no bashism). It uses neither readlink nor realpath. I have verified that it is exactly the same by comparing with GNU readlink -f (see test results). It has error handling and good performance. You can safely replace from readlink -f. The license is CC0, so you can use it for any project.
This code is adopted in the bats-core project.
# POSIX compliant version
readlinkf_posix() {
[ "${1:-}" ] || return 1
max_symlinks=40
CDPATH='' # to avoid changing to an unexpected directory
target=$1
[ -e "${target%/}" ] || target=${1%"${1##*[!/]}"} # trim trailing slashes
[ -d "${target:-/}" ] && target="$target/"
cd -P . 2>/dev/null || return 1
while [ "$max_symlinks" -ge 0 ] && max_symlinks=$((max_symlinks - 1)); do
if [ ! "$target" = "${target%/*}" ]; then
case $target in
/*) cd -P "${target%/*}/" 2>/dev/null || break ;;
*) cd -P "./${target%/*}" 2>/dev/null || break ;;
esac
target=${target##*/}
fi
if [ ! -L "$target" ]; then
target="${PWD%/}${target:+/}${target}"
printf '%s\n' "${target:-/}"
return 0
fi
# `ls -dl` format: "%s %u %s %s %u %s %s -> %s\n",
# <file mode>, <number of links>, <owner name>, <group name>,
# <size>, <date and time>, <pathname of link>, <contents of link>
# https://pubs.opengroup.org/onlinepubs/9699919799/utilities/ls.html
link=$(ls -dl -- "$target" 2>/dev/null) || break
target=${link#*" $target -> "}
done
return 1
}
Please refer to the latest code. It may some fixed.
Better late than never, I suppose. I was motivated to develop this specifically because my Fedora scripts weren't working on the Mac. The problem is dependencies and Bash. Macs don't have them, or if they do, they are often somewhere else (another path). Dependency path manipulation in a cross-platform Bash script is a headache at best and a security risk at worst - so it's best to avoid their use, if possible.
The function get_realpath() below is simple, Bash-centric, and no dependencies are required. I uses only the Bash builtins echo and cd. It is also fairly secure, as everything gets tested at each stage of the way and it returns error conditions.
If you don't want to follow symlinks, then put set -P at the front of the script, but otherwise cd should resolve the symlinks by default. It's been tested with file arguments that are {absolute | relative | symlink | local} and it returns the absolute path to the file. So far we've not had any problems with it.
function get_realpath() {
if [[ -f "$1" ]]
then
# file *must* exist
if cd "$(echo "${1%/*}")" &>/dev/null
then
# file *may* not be local
# exception is ./file.ext
# try 'cd .; cd -;' *works!*
local tmppwd="$PWD"
cd - &>/dev/null
else
# file *must* be local
local tmppwd="$PWD"
fi
else
# file *cannot* exist
return 1 # failure
fi
# reassemble realpath
echo "$tmppwd"/"${1##*/}"
return 0 # success
}
You can combine this with other functions get_dirname, get_filename, get_stemname and validate_path. These can be found at our GitHub repository as realpath-lib (full disclosure - this is our product but we offer it free to the community without any restrictions). It also could serve as a instructional tool - it's well documented.
We've tried our best to apply so-called 'modern Bash' practices, but Bash is a big subject and I'm certain there will always be room for improvement. It requires Bash 4+ but could be made to work with older versions if they are still around.
echo $(cd $(dirname file1) ; pwd -P)
I wrote a realpath utility for OS X which can provide the same results as readlink -f.
Here is an example:
(jalcazar#mac tmp)$ ls -l a
lrwxrwxrwx 1 jalcazar jalcazar 11 8月 25 19:29 a -> /etc/passwd
(jalcazar#mac tmp)$ realpath a
/etc/passwd
If you are using MacPorts, you can install it with the following command: sudo port selfupdate && sudo port install realpath.
Truely platform-indpendent would be also this R-onliner
readlink(){ RScript -e "cat(normalizePath(commandArgs(T)[1]))" "$1";}
To actually mimic readlink -f <path>, $2 instead of $1 would need to be used.
I have simply pasted the following to the top of my bash scripts:
#!/usr/bin/env bash -e
declare script=$(basename "$0")
declare dirname=$(dirname "$0")
declare scriptDir
if [[ $(uname) == 'Linux' ]];then
# use readlink -f
scriptDir=$(readlink -f "$dirname")
else
# can't use readlink -f, do a pwd -P in the script directory and then switch back
if [[ "$dirname" = '.' ]];then
# don't change directory, we are already inside
scriptDir=$(pwd -P)
else
# switch to the directory and then switch back
pwd=$(pwd)
cd "$dirname"
scriptDir=$(pwd -P)
cd "$pwd"
fi
fi
And removed all instances of readlink -f. $scriptDir and $script then will be available for the rest of the script.
While this does not follow all symlinks, it works on all systems and appears to be good enough for most use cases, it switches the directory into the containing folder, and then it does a pwd -P to get the real path of that directory, and then finally switch back to the original.
Perl has a readlink function (e.g. How do I copy symbolic links in Perl?). This works across most platforms, including OS X:
perl -e "print readlink '/path/to/link'"
For example:
$ mkdir -p a/b/c
$ ln -s a/b/c x
$ perl -e "print readlink 'x'"
a/b/c
The answer from #Keith Smith gives an infinite loop.
Here is my answer, which i use only on SunOS (SunOS miss so much POSIX and GNU commands).
It's a script file you have to put in one of your $PATH directories:
#!/bin/sh
! (($#)) && echo -e "ERROR: readlink <link to analyze>" 1>&2 && exit 99
link="$1"
while [ -L "$link" ]; do
lastLink="$link"
link=$(/bin/ls -ldq "$link")
link="${link##* -> }"
link=$(realpath "$link")
[ "$link" == "$lastlink" ] && echo -e "ERROR: link loop detected on $link" 1>&2 && break
done
echo "$link"
This is what I use:
stat -f %N $your_path
The paths to readlink are different between my system and yours. Please try specifying the full path:
/sw/sbin/readlink -f