I am writing a shell script where path can be
~/as-NY/com or ~/as-LN/com whatever is available. I can achieve this in K-shell as
cd ~/as-(NY|LN)/com, but not sure about bash. Can someone help here
In BASH you need to enable extglob and do it like this:
shopt -s extglob
cd ~/as-#(NY|LN)/com
Related
Could you help me, why this script works when sourced (or even directly on console) and does not work on a script?
I have checked and in any case I'm using the same bash in /bin/ and always 4.4.19(1)-release (checked with $BASH_VERSION).
Moreover I tried removing shebang but nothing changes.
#!/bin/bash
fname=c8_m81l_55.fit
bname=${fname%%+(_)+([0-9]).fit}
echo $bname
GIving these results:
test:~$ ./test.sh
c8_m81l_55.fit
test:~$ . ./test.sh
c8_m81l
Bash does not recognize +(pattern) syntax unless extglobs are enabled, and they are disabled by default. Apparently your bash setup enables them in interactive sessions; that's why your script works only when sourced in an interactive shell.
To fix that, either enable extglobs within the script by this command:
shopt -s extglob
Or use an alternative that works irrespective of shell's interactiveness:
bname=$(sed 's/__*[0-9][0-9]*\.fit$//' <<< $fname)
# with GNU sed it'd look like:
bname=$(sed -E 's/_+[0-9]+\.fit$//' <<< $fname)
I'm currently confused why shell globbing in terminal works with negation but shows an error when running in bash.
Take the commands executed in the terminal below, which shows all js files within the ./HTML directory except for js files that ends with .bundle.js.
$ shopt -s globstar
$ ls ./HTML/**/!(*.bundle).js
The command above works perfectly, now let's put it in a bash file
list-js.sh
#!/usr/bin/env bash
shopt -s globstar
ls ./HTML/**/!(*.bundle).js
Executing it in a terminal:
$ bash list-js.sh
list-js.sh: line 4: syntax error near unexpected token `('
list-js.sh: line 4: `ls ./HTML/**/!(*.bundle).js'
As you can see, it shows a syntax error.
globstar only enables the ** pattern. The extglob option allows !(...). Somewhere in your interactive shell, that has already been enabled (perhaps in your .bashrc, perhaps you typed shopt -s extglob earlier). However, it needs to be enabled explicitly in your script, since such settings are not inherited from the shell that starts the script.
#!/usr/bin/env bash
shopt -s globstar extglob
ls ./HTML/**/!(*.bundle).js
(As an aside, ** without globstar does not cause a syntax error because it is treated simply as two adjacent *s, the second one being redundant.)
I'm trying to create a bunch of symbolic links for all the files in a directory. It seems like, when I type this command in the shell manually, it works just fine, but when I run it in a shell script, or even use the up arrow to re-run it, I get the following problem.
$ sudo ln -s /path/to/my/files/* /the/target/directory/
This should create a bunch of sym links in /path/to/my/files and if I type the command in manuall, it indeed does, however, when I run the command from a shell script, or use the up arrow to re-run it I get a single symbolic link in /the/target/directory/ called * as in the link name is actually '*' and I then have to run
$ sudo rm *
To delete it, which just seems insane to me.
When you run that command in the script, are there any files in /path/to/my/files? If not, then by default the wildcard has nothing to expand to, and it is not replaced. You end up with the literal "*". You might want to check out shopt -s nullglob and run the ln command like this:
shopt -s nullglob
sudo ln -s -t /the/target/directory /path/to/my/files/*
Maybe the script uses sh and your using bash when executing the command.
You may try something like this:
for file in $(ls /path/to/my/files/*) do
ln -s "${file}" "/the/target/directory/"${file}"
done
Instead of using default python, in .bashrc I change "python" point to my own python version. However, when I write a bash scripts and call for python in it, it still uses the default python. Why is that, and how can I set it so that I do not have to add "source ~/.bashrc" to every sh file? Thanks
[yl#chh test]$ more test.sh
echo `which python`
[yl#chh test]$ sh test.sh
/usr/bin/python
[yl0#chh test]$ which python
alias python='~/tools/Python-2.7.3/python'
~/tools/Python-2.7.3/python
From the bash man page:
Aliases are not expanded when the shell is not interactive, unless
the expand_aliases shell option is set using shopt (see the
description of shopt under SHELL BUILTIN COMMANDS below).
It would probably be better to change your PATH rather than using an alias for this purpose.
I put the following unsuccessfully to my .bashrc
shopt -s globstar
I am trying to test the command in action by
ls **/*.c
and by comparing it to
ls */*/*.c
How can you enable globstar in Bash 4?
Hmm. shopt -s globstar should work.
To debug, make sure you are running Bash 4:
$SHELL --version
Then check the setting of globstar:
shopt globstar
If it is unset, try setting it manually:
shopt -s globstar
Now see if that works. If it does, you might want to look into why your .bashrc isn't working. Did you remember to restart you shell after editing your .bashrc, or load it with . .bashrc?