π Node [[bash]]
π bash.md by @karlicoss
Table of Contents
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[[shell programming]] [[bash]]
[2017-12-25]boolean return value[2017-12-26]multi-line string varible[2017-12-30]iterate over array- [[assert variable is defined {double square brackets -v} operator]] [[habit]]
[2018-04-26]get current script directory- [avoid passing flags in shebang (e.g.
#!/bin/bash -eu)](#vdpssngflgsnshbnggbnbsh TIDDLYLINK) [[habit]]
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[[interactive tricks & tips]] [[shell]]
[2015-07-23]diff <(ls dir1) <(ls dir2)- [use sigquit {Ctrl-\} to kill processes that are really stuck (when Ctrl-C isn’t working)](#ssgqtctrltkllprcsssthtrrllystckwhnctrlcsntwrkng TIDDLYLINK) [[habit]]
- [exec command on each file
find . -exec some command {} \;](#xccmmndnchflfndxcsmcmmnd TIDDLYLINK) [[drill]] - [exec command in parallel
find /path -iname '*.pdf' -print0 | xargs -0 -n1 -i -P8 bash -c "echo 'Processing {}' && command '{}'"](#xccmmndnprlllfndpthnmpdfptxrgsnpbshcchprcssngcmmnd TIDDLYLINK) [[drill]] [2018-05-08]ps aufxto list all processes- [[tree -pufi for file tree with permissions]] [[habit]]
- [pretty print json
cat file.json | python -mjson.tool](#prttyprntjsnctfljsnpythnmjsntl TIDDLYLINK) [[json]] - [detect if library is installed
ldconfig -p | grep libjpegorgcc -ljpeg](#dtctflbrrysnstlldldcnfgpgrplbjpgrgccljpg TIDDLYLINK) [2015-07-23]merging pdfs- [[{ln -i} for interactive symlink (prompts for removal)]] [[habit]]
- [[use whiptail for ncurses dialogs]] [[tui]] [[habit]]
[2021-01-06]Where is the bash feature to open a command in $EDITOR documented? - Unix & Linux Stack Exchange [[bash]] [[habit]]
Bash & shell programming
shell programming [[bash]]
[2017-12-25] boolean return value
function whatever {
if (x)
then
true
else
false
fi
}
if whatever
then ...
[2017-12-26] multi-line string varible
MULTILINE=$(cat <<-END
here
goes
multi
line
END
)
[2017-12-30] iterate over array
EXTRA_STOWS=("home-arbtt" "home-emacs" "home-anacron")
for s in "${EXTRA_STOWS[@]}"
assert variable is defined {double square brackets -v} operator [[habit]]
[2018-04-26] get current script directory
DIR=$(dirname "$(readlink -f "$0")")
(might not work on mac)
avoid passing flags in shebang (e.g. #!/bin/bash -eu) [[habit]]
e.g. if you specify other flags in terminal, they would override everything
instead, better to use if [[ $0 == "$BASH_SOURCE" ]]; then set -eux; fi
interactive tricks & tips [[shell]]
priorities roughly indicate how useful I find each command
[2015-07-23] diff <(ls dir1) <(ls dir2)
use sigquit {Ctrl-\} to kill processes that are really stuck (when Ctrl-C isn’t working) [[habit]]
exec command on each file find . -exec some command {} \; [[drill]]
exec command in parallel find /path -iname '*.pdf' -print0 | xargs -0 -n1 -i -P8 bash -c "echo 'Processing {}' && command '{}'" [[drill]]
[2018-05-08] ps aufx to list all processes
tree -pufi for file tree with permissions [[habit]]
pretty print json cat file.json | python -mjson.tool [[json]]
detect if library is installed ldconfig -p | grep libjpeg or gcc -ljpeg
[2015-07-23] merging pdfs
pdftk out.pdf j1-process.pdf j1-process-2.pdf j1-process-3.pdf cat output merged.pdf
pdftk full-pdf.pdf cat 1 1 1 2 3 4 12-15 output outfile_p12-15.pdf
{ln -i} for interactive symlink (prompts for removal) [[habit]]
use whiptail for ncurses dialogs [[tui]] [[habit]]
[2021-01-06] Where is the bash feature to open a command in $EDITOR documented? - Unix & Linux Stack Exchange [[bash]] [[habit]]
edit-and-execute-command (C-xC-e)
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