Category Archives: Bash

About bash builtin command named “eval”

ABOUT eval eval is a builtin command of the Bash shell. It concatenates its arguments into a single string, joining the arguments with spaces, then executes that string as a bash command. It’s similar to running bash -c “string”, but eval executes the command in the current shell environment rather than creating a child shell …

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A bash builtin command named “enable” to enable or disable a bash builtin command

[bash light=”true”] $command $echo $? 0 $enable -n command $command bash: command: command not found $echo $? 127 $enable command $command $enable -n enable $enable bash: enable: command not found $ [/bash] RELATED SOURCE CODE EXPOSURE [c light=”true”] /* Enable/disable shell commands present in LIST. If list is not specified, then print out a list …

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Look into bash builtin command named typeset

$typeset -n gree=55 bash: typeset: 55′: invalid variable name for name reference $typeset -n 55=gree bash: typeset:55=gree’: not a valid identifier$typeset -n gree=pwd$echo $gree $echo $pwd $typeset -n vary=$?bash: typeset: `0′: invalid variable name for name reference$typeset vary=$?$echo $vary1$echo $vary1$echo $?0$echo $vary1$echo varyvary$echo $vary1$echo $vary1$echo $?0$typeset vary=$?$echo $vary0$ $typeset hello $echo $hello $echo $? 0 …

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How to use dirs, pushd and popd commands ?

$pushd upstream-kernel/ ~/upstream-kernel ~ $pwd /home/jeffrin/upstream-kernel $cd .. $pushd temp/ ~/temp ~ ~ $dirs ~/temp ~ ~ $dirs -l /home/jeffrin/temp /home/jeffrin /home/jeffrin $pwd /home/jeffrin/temp $pushd ../upstream-kernel/ ~/upstream-kernel ~/temp ~ ~ $dirs -l /home/jeffrin/upstream-kernel /home/jeffrin/temp /home/jeffrin /home/jeffrin $pushd ../testing/ ~/testing ~/upstream-kernel ~/temp ~ ~ $dirs -l /home/jeffrin/testing /home/jeffrin/upstream-kernel /home/jeffrin/temp /home/jeffrin /home/jeffrin $popd ~/upstream-kernel ~/temp ~ ~ …

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finding source code or source file of a typical bash function

$type -a signals bash: type: signals: not found $type -a _signals _signals is a function _signals () { local -a sigs=($( compgen -P “$1” -A signal “SIG${cur#$1}” )); COMPREPLY+=(“${sigs[@]/#${1}SIG/${1}}”) } $declare -F _signals _signals $shopt -s extdebug $declare -F _signals _signals 862 /usr/share/bash-completion/bash_completion $declare -F _command _command 1732 /usr/share/bash-completion/bash_completion $declare -F compgen $declare -F _grub_dirs …

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bash builtin command named command

$pwd /home/jeffrin/upstream-kernel $tail ~/.bashrc . /usr/share/bash-completion/bash_completion elif [ -f /etc/bash_completion ]; then . /etc/bash_completion fi fi export PS1=$ function ls { pwd } $ls /home/jeffrin/upstream-kernel $command ls 0002-Testing-script-for-Intel-P-State-driver-crashes-duri.patch linux linux-kselftest linux-kselftest.bup linux-kselftest.bup2 linux-next linux.old $

caller — returns the context of any active subroutine call

$cat test.bash!/bin/bash die() { local frame=0 while caller $frame; do ((frame++)); done echo “$*” exit 1 } f1() { die “*** an error occured ***”; } f2() { f1; } f3() { f2; } f3 $ $bash test.bash 12 f1 test.bash 13 f2 test.bash 14 f3 test.bash 16 main test.bash *** an error occured *** …

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