Questions tagged [bash]
Questions specific to GNU’s Bourne Again SHell, as opposed to other Bourne/POSIX shells. For questions about Unix shells in general, use the /shell tag instead. For shell scripts with errors/syntax errors, please check them with the shellcheck program (or in the web shellcheck server at https://shellcheck.net) before posting here.
3,022
questions with no upvoted or accepted answers
18
votes
1
answer
3k
views
zsh can't input to terminal when piping stdin and stdout with variable command that has tty output
System info:
macOS Sierra 10.12.6
zsh 5.4.2 (x86_64-apple-darwin16.7.0)
GNU bash, version 4.4.12(1)-release (x86_64-apple-darwin16.3.0)
Scroll to the EXAMPLES at the bottom if you just want to dig ...
- 498
7
votes
0
answers
232
views
Bash script containing sudo - unreliable background resume (bg)
I have the following simple bash script (called test.sh), that shows disk usage in the root dir. sudo is needed to list all directories (and I'm not asked for sudo password).
#!/bin/bash
sudo du -h --...
- 682
7
votes
1
answer
2k
views
Moving cursor to end of line when using history-search-backward
I recently added the following lines to my .inputrc:
"\e[A": history-search-backward
"\e[B": history-search-forward
However, I noticed when using this that my cursor does not jump ...
- 181
6
votes
0
answers
1k
views
Equivalent of PSReadLine for bash
For my Windows Terminal using Powershell I have the plugin PSReadline which gives me some pretty handy features. For instance a navigatable list view of my history when I start typing. So if I type cd ...
- 161
6
votes
2
answers
2k
views
Sending SIGINT to process groups sometimes gets ignored
I start a process group from bash. Then I send SIGINT to the entire process
group. Sometimes the SIGINT kills the processes, sometimes does not. Why does
SIGINT sometimes gets ignored ?
I see ...
- 809
6
votes
1
answer
2k
views
Logging the output of remote commands on multiple ssh servers without delay
I've written a simple bash script that ssh's into 3 hosts (2 remote, 1 my own for testing) and runs a long running gui program that outputs text to the terminal that I'd like to log.
#!/bin/bash
ssh ...
- 161
6
votes
1
answer
1k
views
bash/gnu readline multiline command: move row up/down
How to move one editing row up (back) or down (forward) in a multi-line command in bash/readline?
Somethnig like gj/gk in Vim.
- 291
5
votes
1
answer
185
views
Why does bash print exit even when it does not exit - is this a bug?
exit with zero or one numeric argument like exit or exit 42 print "exit" and exit the shell.
exit with an invalid argument like exit hello prints an error message, prints "exit" ...
- 153
5
votes
0
answers
944
views
Kernel module remove not permitted for some sudo users
I use a sudoers file, which (besides other items) contains following lines:
homebridge ALL=(ALL) NOPASSWD: /sbin/modprobe -r bcm2835-v4l2, /sbin/modprobe bcm2835-v4l2, /sbin/reboot
%sudo ...
- 151
5
votes
0
answers
958
views
Merge stdout and stderr, and create copies of each separately
My goal is best explained by example. To start, here's
a function that will produce sample output, on both stdout and
stderr:
output() {
printf '%s\n' 1 2
printf '%s\n' errA errB 1>&2
...
- 1,049
5
votes
2
answers
2k
views
How to stop marking while in tmux copy-mode?
I want to mark and copy text, and then stay in copy-mode with the marker off, permitting me to move up/down without marking new text (see below).
But after marking text and pressing space or y to ...
- 4,073
5
votes
0
answers
278
views
Bash completion own compgen prefix
I have a simple bash completion script that essentially invokes my (non-bash) program and set its output to COMREPLY, i.e.
COMPREPLY=( $(my-program -- "${COMP_WORDS[@]}") )
Some of the options ...
- 161
5
votes
1
answer
858
views
How can I properly use an American flag emoji in my bash prompt?
I want to use an American flag emoji in my bash prompt (i.e. PS1 environment variable). However, the American flag emoji causes the terminal cursor to offset an extra character to the right.
🇺🇸 is ...
- 151
5
votes
1
answer
497
views
Pasting into terminal including comments issue
This is somehow a follow-up to my last question: Pasting multiple commands into terminal stops at user input
Pasting the following to the terminal works as expected:
(
echo test1
# some comment
echo ...
- 22.3k
5
votes
1
answer
2k
views
TOR hidden service not always accessible through cURL. Takes multiple tries
When I try to access a hidden service on TOR using cURL, for some reason I'm not getting access to the site 100% of the time. Many times it returns "curl: (7) Can't complete SOCKS5 connection to 0.0.0....
- 201
5
votes
1
answer
634
views
Assign both menu-complete and dynamic-complete-history to TAB
Is there a way for me to assign both menu-complete and dynamic-complete-history to Tab (or one to Tab and the other to Tab-Tab) in .inputrc?
I'm thinking there might be a way to setup a function and ...
- 99
5
votes
1
answer
256
views
git report moved lines
I want to track the number of additions and deletions that exclude moved lines. So if a commit has 10 additions, 5 deletions, and 3 moved lines, then I have 7 additions, 2 deletions excluding moved ...
- 191
4
votes
0
answers
42
views
Name of background job started from EXIT trap is wrong
The following script:
#!/bin/bash
set -m
atexit() {
sleep 1 &
jobs
}
trap atexit EXIT
echo Hello world
Produces this output:
$ bash ./foo.sh
Hello world
[1]+ Running ...
- 861
4
votes
1
answer
3k
views
E: The repository 'http://security.ubuntu.com/ubuntu impish-security Release' does not have a Release file
when I try to command :
sudo apt update
this error was shown:
E: The repository 'http://security.ubuntu.com/ubuntu impish-security Release' does not have a Release file.
N: Updating from such a ...
4
votes
1
answer
335
views
What is the purpose of a pipe after stdout redirect?
I was reading the documentation for Kaniko and saw a shell redirect-then-pipe construct that I haven't seen before:
echo -e 'FROM alpine \nRUN echo "created from standard input"' > ...
- 141
4
votes
0
answers
339
views
How to cancel edit-and-execute-command?
Is there a way to not execute a command, once I have pressed Ctrl+X Ctrl+E? (edit-and-execute-command)
Ideally like in git: If I save the file (like :wq in vim), it gets executed, but if I close the ...
- 223
4
votes
0
answers
345
views
Configuration or command to for case insensitive bash history search
Bash provides the interactive commands forward-search-history and reverse-search-history typically bound to the keys CTRL-s and CTRL-r respectively.
Are there case-insentive equivalents or is there a ...
- 826
4
votes
0
answers
185
views
Why does bash $LINENO change inside an inner block in a function?
I'm trying to debug auto completion script located in /usr/share/bash-completion/bash_completion (bash completion package on every distro)
I did
export PS4='+'$'\t''$LINENO'$'\t # \t for proper ...
- 137
4
votes
0
answers
347
views
bash [-+]O shopt_name doesn't work the way it's supposed to as per by the manual
The bash manual says:
"
[-+]O [shopt_option]
shopt_option is one of the shell options accepted by the
shopt builtin (see SHELL BUILTIN COMMANDS below). If
...
4
votes
0
answers
447
views
bash + how to avoiding duplicate entries in authorized_keys (ssh) in bash
Popular methods of adding an ssh public key to a remote host’s authorized_keys file include using the ssh-copy-id command, and using bash operators such as >> to append to the file.
An issue ...
user436442
4
votes
0
answers
492
views
HISTCONTROL - When is erasedups executed?
I know that ignorespace and ignoredups work in real time and prevent entries going into the buffer, but when does erasedups come into play?
Is it when the buffer is written/appended, is it when the ...
- 305
4
votes
0
answers
326
views
Is there a command like `time` that monitors the network traffic of commands?
I can use the time command to measure the time some command takes:
time node -e ""
node -e "" 0.06s user 0.01s system 92% cpu 0.076 total
Is there a similar way to measure a ...
- 1,493
4
votes
0
answers
179
views
On MacOS, what character does `Esc+` or `+Esc` correspond to in Bash, when using iTerm2 terminal?
I've read that mapping Left Option key to Esc+ should fix many of the issues users of Bash, on MacOS, have with GNU Readline key-bindings.
However, I've never encountered Esc+ or +Esc before, so does ...
- 4,073
4
votes
0
answers
722
views
What are exactly shells levels?
My understanding of shell levels and sub-shell was that:
Sub-shells are forks (but not execs) of the shell process created by ( ... ) constructs.
$SHLVL counts shell execs.
$BASH_SUBSHELL counts sub-...
4
votes
0
answers
2k
views
chmod always gives "illegal option" error
No matter what chmod command I run, I am always getting
chmod: illegal option -- -
usage: chmod [-fhv] [-R [-H | -L | -P]] [-a | +a | =a [i][# [ n]]] mode|entry file ...
chmod [-fhv] [-R [-H | -...
- 71
4
votes
0
answers
364
views
Colorize the PS4 prompt?
With the option set -x, each command is echoed to STDERR before execution, prefixed by the expanded $PS4, with the first character being repeated according to the call stack depth.
I want the output ...
- 199
4
votes
1
answer
1k
views
Adding "sudo" commands to the bash history of the *target* user
Something that's bothered me for many years is that if I want to search my shell history for commands which were run as root, I have to check two different locations:
I have to check /root/....
- 146
4
votes
1
answer
746
views
Nested command substitution does not stop a script on a failure even if -e and shopt -s inherit_errexit are set
Suppose you have a following script sandbox.sh.
(This looks similar to Command substitution inside a function does not stop the script on a failure even if -e is set, but I believe a bit different ...
- 167
4
votes
0
answers
991
views
How to show rsync progress when running as systemd service
I have a bash script sync_nodes.sh that I want to manage with a systemd unit sync_nodes.service.
I want the progress of of the rsync command to show up in my logs. When I run the command ...
- 2,928
4
votes
0
answers
745
views
How to keep screen running after exiting the command that runs in it?
I have the task to start a detached screen session (e.g. when the system reboots) and then to be able to connect to it and interrupt/kill the running process without the screen to terminate. ...
- 141
4
votes
3
answers
4k
views
How to execute script on remote server after loggin in through ssh
I'm managing a bunch of servers so I frequently have to ssh into them. I'd like to automatically run a basic custom script on whatever remote server after logging in. Say to set up some aliases, ...
- 771
4
votes
0
answers
499
views
Is it possible to fork the current pane in tmux and put it in a new pane?
Often I have set up some temporary environment variables/modules and I would like them to persist as I create a split in Tmux. Is it possible to fork the current running program (i.e. bash) and put ...
- 213
4
votes
0
answers
5k
views
Bash script calls python script that wants interactively input ( not only arguments )
I have a bash script bash.sh that looks like this:
#!/usr/bin/env bash
/usr/local/sbin/pythonScript.py firstArgument secondArgument
If I call the pythonScript.py from my terminal with the two ...
- 161
4
votes
0
answers
3k
views
Will a child process be in a different process group than the parent process?
I always thought that a child process will be in the same process group as the parent process. But I have read the following from here:
if you run some_app from the shell, the shell creates a new ...
- 93
4
votes
0
answers
1k
views
How to bind to ctrl+x in bash?
I appear to be using GNU bash, version 4.4.12, though it's possible my organization has modified it from HEAD. I'm trying to bind ctrl+x:
$ bind -x '"\C-t": "echo testing"'
<I press ctrl+t>
...
- 163
4
votes
1
answer
411
views
is it possible to colors the prompt for (reverse-i-search) context menu?
I am using fedora 25 but I think this is a general behavior on unix system.
When I ctrl+r in a command-line environment I can start to type in and anything I type will get to be matched backward in ...
- 1,696
4
votes
0
answers
1k
views
How to set the default color of output / things typed in Bash
When I am typing or viewing text on my terminal, the color is white. Any command after I type my prompt is white, and the default output (stdout) is white.
I looked and my terminal emulator does not ...
- 1,839
4
votes
0
answers
1k
views
Coloring terminal commands ("syntax highligting" on command line)
I do know I can color my prompt using escape sequences in the PS1 variable.
Now, I would like to know if there is a way to put some color on the bash commands I often use, on the command line itself.
...
4
votes
0
answers
288
views
How to explicitly set the tabname of a new gnome-terminal?
I want to explicity rename a tab in gnome-terminal on startup of the tab. I don't want to use gnome-terminal --title flag as that gets reset by my systems bashrc file after whatever else is supposed ...
- 141
4
votes
2
answers
457
views
bash/cygwin broken after installing rtool?
Usually I can solve problems on my own (and Google). But recently I am baffled by this strange hiccup.
Background:
I use a chain of scripts for file-processing (in Windows, under Cygwin. Scripts ...
- 969
4
votes
0
answers
1k
views
Bash command history stops working after starting new tmux session
My bash command history stops working after starting a new tmux session. No previous commands when typing up, down, reverse search, no output from running history.
I've confirmed that this happens ...
- 141
4
votes
0
answers
613
views
Replacing a running binary on read-only file system
I have a simple updater bash script, which replaces files by removing the incident old files and copying new files from an archive to the running embedded target root file system. This way, the script ...
- 181
4
votes
1
answer
436
views
Bash prompt - backspace deletes right aligned text (possible to stop?)
I have a really annoying problem. I have followed all of the protocol for making a bash PS1. I know about surrounding non-printable characters with \[ and \] or \001 and \002; however, I have a ...
- 435
4
votes
0
answers
344
views
Bash command not found due to stray garbage characters
What is the cause of this behavior?
$ cd ../
$ bash: $'\210\210cd': command not found
This happens sometimes (rarely) when I enter a command, there is no visible character preceding the cd, still it ...
4
votes
2
answers
524
views
Context-sensitive bash completion changes wildcard behavior
Somewhere along the way I've fallen into the habit of hitting tab twice after using a wildcard in commands like mv or rm, which by default causes bash to show the list of files that would match the ...
- 396