1. cat¶
In [22]:
cat -A a.txt # -vET (All: non-printable, end of lines, tabs)
In [29]:
tr -dc '[:print:]\n' < a.txt | cat -A # delete, complement set1
In [32]:
cat -n txt
In [17]:
cat -ns txt
In [37]:
cat -b txt
In [44]:
cat -b < txt | sed /^$/d
2. tac¶
In [54]:
grep -v '^#' /etc/default/hddtemp | sed '/^$/d' > hddtemp
In [55]:
cat hddtemp
In [56]:
tac hddtemp
In [ ]:
dmesg | tac
3. sort¶
In [53]:
ls -l /etc/grub.d | head -5
In [4]:
ls -l /etc/grub.d | head -5 | sort -k5 -t ' ' # key [field,to field] | separator
In [6]:
ls -l /etc/grub.d | head -5 | sort -n -r -k5,5
In [170]:
cat txt
In [171]:
sort txt
In [14]:
sort -k1,1 -k2,2n txt
In [24]:
ls -lF /etc/network | sort -k8.4 #char4 in key8
4. uniq¶
In [38]:
cat txt
In [62]:
sort txt | uniq -i # makes output unique, ignore case
In [40]:
sort txt | uniq -c # count
In [41]:
sort txt | uniq -d # only duplicates
In [43]:
sort txt | uniq -u # only uniqe rows
In [50]:
ln txt h-txt; ln txt h2-txt
In [55]:
find -maxdepth 1 -type f -links +1 -printf "%p %i\n" | tee out
In [59]:
sort out | uniq -d
In [61]:
sort out | uniq -f1 -dc # -f skip n first field
5. cut¶
In [72]:
head /etc/group | grep adm
In [69]:
cat /etc/group | grep milad | cut -f1 -d: | tr '\n' ' ' | xargs echo
In [70]:
id milad -Gn
In [81]:
head -4 /etc/passwd | cut --complement -f2-4,7 -d:
In [157]:
date | tee txt | cat -A
In [158]:
cut -f4 -d' ' < txt
In [159]:
tr -s ' ' < txt | cut -f4 -d' ' | cut -c 4- # tr: -s, --squeeze-repeats
6. paste¶
In [27]:
head -5 /etc/passwd
In [29]:
cut -f1,7 /etc/passwd -d: | head -5
In [30]:
cut -f2-6 --complement /etc/passwd -d: | head -5
In [32]:
head -5 /etc/passwd | cut -f1 -d: | tee users
In [34]:
head -5 /etc/passwd | cut -f7 -d: | tee shells
In [44]:
paste shells users -d':'
7. join¶
In [10]:
cat namev; echo ---; cat namet;
In [11]:
join namev namet
In [14]:
cat namev; echo ---; cat namet;
In [16]:
join -1 2 -2 1 namev namet # -j when both are same
8. comm¶
Compare sorted files FILE1 and FILE2 line by line.
When FILE1 or FILE2 (not both) is -, read standard input.In [29]:
cat f1; echo ---; cat f2
In [26]:
comm f1 f2
In [9]:
comm -3 f1 f2 # do not show 3
In [12]:
echo - | cat f1 - f2
In [13]:
diff f1 f2
Line 2 to 3 from file one has been changed in file two.
We should replace them with 2 to 4 from file two to make them same.
In [18]:
echo - | cat f1 - f2
In [19]:
diff f1 f2
After line 2 in file one, add line 3 from file two (which is yellow)
In [21]:
echo - | cat f1 - f2
In [23]:
diff f1 f2
9.2. Context¶
- \s\s Same
- ! Change
- - Remove from first file
- + Add from second to first one
In [30]:
echo "__-_-_-__" | cat f1 - f2
In [78]:
diff -c f1 f2
Apply the changes to f1:¶
Ardabil -> Tehran,
Remove Esfehan,
Add shiraz
In [34]:
diff f1 f2
9.3. Unified¶
In [79]:
diff -u f1 f2
9.4. Column¶
In [80]:
diff -y f1 f2
In [81]:
diff f1 f2 # check with default output
9.5. Create an ed script¶
In [39]:
diff f1 f2 -e > changes
In [40]:
cat changes
In [41]:
echo 'w' >> changes # hey ed write to file ;)
In [42]:
cat f1 # before running ed
In [43]:
ed < changes f1
In [44]:
cat f2 # after ed did the job
In [45]:
diff f1 f2
In [46]:
md5sum f1 f2
10. patch¶
In [58]:
diff f1 f2
In [68]:
diff -u f1 f2 > diff
In [69]:
cat diff
In [70]:
patch < diff
In [71]:
cat f1
11. tr¶
In [82]:
echo "Here is some text." | tr -d ' '
In [93]:
tr -c -d '[:upper:]\n' < f1
In [95]:
echo "Hi_this_is_a-TEST" | tr '[:upper:]_-' '[:lower:] '
Lecture notes¶
- All lecture notes are available at github in
ipynbformat: https://github.com/ravexina/linux-notes.
- There are
htmlexports of project available at: https://ravexina.github.io/linux-notes.
License¶
Linux Notes by Milad As (Ravexina) is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
