メインコンテンツまでスキップ

FAQ: bash

🆀 .bashrcなどのシェル設定ファイルの読み込み順について教えてください​

🅐 読み込み順についての正式な情報源は、bash(1)マニュアルです。(man bashコマンドで表示できます。)

以下 4 つの場合でシェル設定ファイルの読み込み順が異なります。bash(1)マニュアルの該当の記載を併記します。

1, interactive, login shell​

ssh でログインした場合やsu -を実行した場合など。(su -はsu --loginと同じ。ログインシェルとしてシェルを起動せよの意味。) qloginした場合もこれに該当します。

~/.bash_profile, ~/.bash_login, ~/.profileの順で探して最初に存在したファイルを読み込みます。

When bash is invoked as an interactive login shell, or as a non-interactive shell with the --login option, it first reads and executes commands from the file /etc/profile, if that file exists. After reading that file, it looks for ~/.bash_profile, ~/.bash_login, and ~/.profile, in that order, and reads and executes commands from the first one that exists and is readable. The --noprofile option may be used when the shell is started to inhibit this behavior.

したがって bash の動作としては SSH でログインした際には~/.bashrcは自動的には読み込まれませんが、 上記のシェル設定ファイルの中に~/.bashrcを読み込むように書かれている場合が多い、という関係にあります。

2, interactive, non-login shell​

ターミナルエミュレータを起動した場合や、screen, emacs の shell-mode を起動した場合など。

~/.bashrcが読み込まれます。

When an interactive shell that is not a login shell is started, bash reads and executes commands from ~/.bashrc, if that file exists. This may be inhibited by using the --norc option. The --rcfile file option will force bash to read and execute commands from file instead of ~/.bashrc.

  • 注意: GNU screen と同じような機能を持つポピュラーなソフトウェアとしてtmuxがありますが、tmuxを起動するとデフォルトでは bash はログインシェルとして起動します。

3, non-interactive, login shell​

scp を実行する場合や、ローカルマシンにあるスクリプトをリモートサーバ上で実行する場合がこれに当たります。

ssh you@remotehost 'bash -s' < local_script.sh

~/.bashrcが読み込まれます。

Bash attempts to determine when it is being run with its standard input connected to a network connection, as when executed by the remote shell daemon, usually rshd, or the secure shell daemon sshd. If bash determines it is being run in this fashion, it reads and executes commands from ~/.bashrc, if that file exists and is readable. It will not do this if invoked as sh. The --norc option may be used to inhibit this behavior, and the --rcfile option may be used to force another file to be read, but rshd does not generally invoke the shell with those options or allow them to be specified.

4, non-interactive non-login shell​

シェルスクリプトを実行した場合など。

シェル設定ファイルは読み込まれません。

参考資料

🆀 環境を初期状態に戻したいのですが、どのようにしたらよいでしょうか。(Ubuntu Linux 22.04 の場合)​

🅐 環境を初期状態に戻すには.bash_profile, .bashrcを以下の状態に戻してログインし直してください。

.bash_profile​

source ~/.bashrc

.bashrc​

# If this variable is already set, skip the rest of the script
if [ -n "$BASHRC_LOADED" ]; then
    return
fi

# Set the variable to indicate that the script has been loaded
BASHRC_LOADED=1

# ---

# ~/.bashrc: executed by bash(1) for non-login shells.
# see /usr/share/doc/bash/examples/startup-files (in the package bash-doc)
# for examples

# If not running interactively, don't do anything
case $- in
    *i*) ;;
      *) return;;
esac

# don't put duplicate lines or lines starting with space in the history.
# See bash(1) for more options
HISTCONTROL=ignoreboth

# append to the history file, don't overwrite it
shopt -s histappend

# for setting history length see HISTSIZE and HISTFILESIZE in bash(1)
HISTSIZE=1000
HISTFILESIZE=2000

# check the window size after each command and, if necessary,
# update the values of LINES and COLUMNS.
shopt -s checkwinsize

# If set, the pattern "**" used in a pathname expansion context will
# match all files and zero or more directories and subdirectories.
#shopt -s globstar

# make less more friendly for non-text input files, see lesspipe(1)
[ -x /usr/bin/lesspipe ] && eval "$(SHELL=/bin/sh lesspipe)"

# set variable identifying the chroot you work in (used in the prompt below)
if [ -z "${debian_chroot:-}" ] && [ -r /etc/debian_chroot ]; then
    debian_chroot=$(cat /etc/debian_chroot)
fi

# set a fancy prompt (non-color, unless we know we "want" color)
case "$TERM" in
    xterm-color|*-256color) color_prompt=yes;;
esac

# uncomment for a colored prompt, if the terminal has the capability; turned
# off by default to not distract the user: the focus in a terminal window
# should be on the output of commands, not on the prompt
#force_color_prompt=yes

if [ -n "$force_color_prompt" ]; then
    if [ -x /usr/bin/tput ] && tput setaf 1 >&/dev/null; then
	# We have color support; assume it's compliant with Ecma-48
	# (ISO/IEC-6429). (Lack of such support is extremely rare, and such
	# a case would tend to support setf rather than setaf.)
	color_prompt=yes
    else
	color_prompt=
    fi
fi

if [ "$color_prompt" = yes ]; then
    PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ '
else
    PS1='${debian_chroot:+($debian_chroot)}\u@\h:\w\$ '
fi
unset color_prompt force_color_prompt

# If this is an xterm set the title to user@host:dir
case "$TERM" in
xterm*|rxvt*)
    PS1="\[\e]0;${debian_chroot:+($debian_chroot)}\u@\h: \w\a\]$PS1"
    ;;
*)
    ;;
esac

# enable color support of ls and also add handy aliases
if [ -x /usr/bin/dircolors ]; then
    test -r ~/.dircolors && eval "$(dircolors -b ~/.dircolors)" || eval "$(dircolors -b)"
    alias ls='ls --color=auto'
    #alias dir='dir --color=auto'
    #alias vdir='vdir --color=auto'

    alias grep='grep --color=auto'
    alias fgrep='fgrep --color=auto'
    alias egrep='egrep --color=auto'
fi

# colored GCC warnings and errors
#export GCC_COLORS='error=01;31:warning=01;35:note=01;36:caret=01;32:locus=01:quote=01'

# some more ls aliases
alias ll='ls -alF'
alias la='ls -A'
alias l='ls -CF'

# Add an "alert" alias for long running commands.  Use like so:
#   sleep 10; alert
alias alert='notify-send --urgency=low -i "$([ $? = 0 ] && echo terminal || echo error)" "$(history|tail -n1|sed -e '\''s/^\s*[0-9]\+\s*//;s/[;&|]\s*alert$//'\'')"'

# Alias definitions.
# You may want to put all your additions into a separate file like
# ~/.bash_aliases, instead of adding them here directly.
# See /usr/share/doc/bash-doc/examples in the bash-doc package.

if [ -f ~/.bash_aliases ]; then
    . ~/.bash_aliases
fi

# enable programmable completion features (you don't need to enable
# this, if it's already enabled in /etc/bash.bashrc and /etc/profile
# sources /etc/bash.bashrc).
if ! shopt -oq posix; then
  if [ -f /usr/share/bash-completion/bash_completion ]; then
    . /usr/share/bash-completion/bash_completion
  elif [ -f /etc/bash_completion ]; then
    . /etc/bash_completion
  fi
fi

🆀 環境を初期状態に戻したいのですが、どのようにしたらよいでしょうか。(CentOS 7 の場合)​

🅐 アカウント作成直後の.bash_profile, .bashrcは以下のとおりです。 これらのファイルをこの状態に戻してログインし直してください。

.bash_profile​

# .bash_profile

# Get the aliases and functions
if [ -f ~/.bashrc ]; then
	. ~/.bashrc
fi

# User specific environment and startup programs

PATH=$PATH:$HOME/.local/bin:$HOME/bin

export PATH

.bashrc​

# .bashrc

# Source global definitions
if [ -f /etc/bashrc ]; then
	. /etc/bashrc
fi

# Uncomment the following line if you don't like systemctl's auto-paging feature:
# export SYSTEMD_PAGER=

# User specific aliases and functions
module load gcc
に最終更新
RSS FeedJSON Feed