5/20/2018 UNIX - Linux Shell Cheat Sheet
1/2
A full PDF and online tutorial is available at
http://steve-parker.org/sh/sh.shtml
v1.1 7 Aug 2007
UNI / !inu" #hell $heat #heet
File %anipulation &est 'perators (ariable #ubstitution
> file create (overwrite) file
>> file append to file # do something
>file 2>1 !oth output and errors to file "$%&err' "$
or err* if unset
+ file read from file
a , ! pipe output from -a- as input to -!- Numeri) &ests
$onditional *"e)ution
less than c1 ,, c2 run c1 if it fails run c2
$ommon $onstru)ts greater than c1 c2 run c1 if it wor/s run
c2while read f eual to
do read tet not eual $ommon utilities and s+it)hes
echo ine is "f* file line greater or eual list files !iggest
last
done + file !3 line le less or eual list files newest last
File &ests director3 si4es (slow)find newer than sort 5n
sort numericall3 (not alpha)
matching d is a director3 list m3 commands
lines f is a file download 6
r reada!le
get field w writea!le touch file create file
with delimiter eecuta!le read read * from /e3!oard
get output #tring &ests
of command 8 eual to
4 4ero length
n not 4ero length Net+orking
a) case is a good list all networ/ interfaceswa3 to avoid
!ogi)al &ests show routers
iterating logical A9: log in to host as user u*
!) through man3 ,, logical ;
< logical 9;= user u*
constructs.
) Argument (ariables
"0 program name less file displa3 file page !3 page
"1 alias l8-ls 5l- create l* as alias for ls 5l*
"2
... ... list?of?files
function "@ displa3 a calendar (ar 7B)
declaration " all arguments show dis/ mounts
' and calling "# 9o. of arguments truss 5p CD:
s3nta
Files: $ontents / Attributes
A for loop find . 5si4e 10/ 5print files over 10E!
for i in iterates through find tet files
do its input (which ls all directories
echo File is "i* is su!Gect to
done simple maths
!etter maths
Useful (ariables !ar* in file"DFH Dnternal File Heparator
"& return code from last program of each line
"HIJ what shell is running this script&
A9K anguage L is 6H Jnglish file with !ar*
http%MMsteve5par/er.orgMshMsh.shtml
if N "* 5lt "3* O then "$%5def' "$ or def* if unset
"$%8def' "$ (set to def* if unset)
fi
lt
gt
e
ne
ge ls 5lHr
ls 5ltr
ls 5lh human5reada!le filesi4es
" grep foo m3file du 5s/ afoo nt
foo ps 5ef
foo!ar wget 6
time cmd stopwatch on PcmdP
" cut 5d% 5fQ MetcMpasswd
:il!ert
cmd , R cmd output to stdout and
foo8PlsP tee file.tt also to file.tt
nice cmd run cmd with low priorit3
case "foo in
ifconfig 5a echo foo is A* netstat 5r
sshuShost
scp file.tt R cop3 file.tt to host as
echo foo is T* ifMelifMelifMelif uShost%
,eneral Admin
echo foo is not A or T*
1stargument
esac 2ndargument tar cf t.tar R create a tar archive t.tar
from the listed dirsMfiles
dou!leit() @thargument cal B 1@7B
epr "1 R 2 df 5h
show s3scalls of CD:
dou!leit B # returns U
find . 5name .tt* 5print
find Mfoo 5t3pe d 5ls
under Mfoo
glo!!ing) three8Pepr 1 V 2P
echo Wscale 8 Q Q121 M 102X* , !c
egrep (foo,!ar)* file find foo* or
aw/ - print "Q '- file print the Qthword
sed sMfooM!arMg file replace foo* in
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